Weeds:Key(TEXT)

WEED TAXONOMY

Use Table of Contents for Textual Key

Key to Crop Weed Pests

GRASS WEEDS

Grass Weed Crop Pests

WHORLED INFLORESCENCE (WHORLED FLOWER)

(1) Cynodon dactlyon (Bermudagrass)

Grass low, mat-forming, strong but thin stolons; short, sometimes crowded internodes bearing many blades along stem; sprouting roots at lower nodes; spikelets small (1.8-2.8 mm long), pointed at tip.

(2) Dactyloctenium (Crowfootgrass)

Spikelets attached on only one side of the rachis; rachis projecting as a point beyond the inflorescence; native to warmer parts of the eastern hemisphere; D. aegyptium introduced in the Americas, weed of disturbed sites and coastal sands.

(3) Digitaria (Crabgrass)

Spikelets on very short (up to 2 mm long) pedicels; some actually sessile; spikelets departing from the rachis on opposite sides; inflorescence up to 3 mm wide; culm round, but rachis 3-angled (triangular in cross-section); may root at lower nodes and form mats. Most species grow on moist, disturbed sites.

(4) Eleusine indica (Goosegrass)

Spikelets sessile, departing from rachis on only 2 sides, forming two rows opposite each other, extending up the rachis; culm flattened, inflorescence up to .75 mm wide; found in warmer regions of both hemispheres, frequent on disturbed soil in southern U.S.

(5) Pasplum (Dallisgrass/Bahaigrass)

Grass not mat-forming; strong, thick (to 1.5 cm) rhizomes; internodes not crowded; spikelets rounded, elliptical or oval, sometimes flat on one side and rounded on the other; often found in wet habitats.

CONTRACTED INFLORESCENCE (CONTRACTED FLOWER)

(1) Phleum pretense (Timothy)

Perennial, growing erect. The base of the plant may have 1-3 bulb-shaped structures. Seed head is green and may have purple tinged spikelets. Spikelets are small (2-5.2 mm long), flattened, and have tiny, fine awns (0.6-2 mm long). Ligule is a 1-6 mm long membrane.

(2) Setaria (Foxtail)

Many species in this genus are annuals. Culms are often bent at the nodes. Awnlike bristles protrude from the rachis, giving the cylindrical inflorescence a fuzzy appearance. Spikelets are ovate in outline, and flat on on side. Ligule is a ring of hairs or membrane with hairs.

SPIKE/SPIKELIKE INFLORESCENCE (SPIKE AND SPIKELIKE FLOWER)

(1) Elymus (Quackgrass)

Perennial, growing erect. Spikelets alternating up 2 sides of rachis; spikelets usually 1 per node, sometimes 2; often with well-developed auricles; blades flat or rolled.

(2) Elymus elymoides (Squirreltail)

Spikelet (excluding awns) between 6-12 mm long; spikelets loosely overlapping; awns between 2-12 cm long; some bent backwards as to almost form a 90 degree angle; inflorescence readily falling apart at maturity.

HABITAT: (Stubbendieck, p. 215) "dry hills, plains, open woods, and rocky slopes of deserts; most abundant on disturbed sites on either deep or shallow soils; may grow in saline or alkaline soils."

NOTE: (Stubbendieck) Forage value is "fair for cattle and horses and poor for sheep before inflorescences develop, may be consumed in late summer and early fall after inflorescences have broken and fallen, unpalatable during winter."

(3) Hordeum jubatum (Foxtail barley)

Spikelet (excluding awns) between 5.5-8 mm long; spikelets tightly overlapping; awns seldom bent so far backward as to form a 90 degree angle; inflorescence falling apart at maturity.

HABITAT: (Stubbendieck p. 211) "open ground, meadows, waste places, and alkaline and saline sites; adapted to a broad range of soil types, most abundant where water accumulates."

NOTE: (Stubbendieck) Forage value "poor for all classes of livestock and wildlife, it may be lightly grazed before inflorescence development, presence in hay greatly reduces hay value; awns may cause sore in and around the nose, eyes, and mouth and contaminate fleece."

(4) Lolium (Ryegrass)

Spikelets arranged sideways to rachis.

(5) Polypogon (Rabbitfoot grass)

Grass without rhizomes; spikelets tiny (to 2 mm long), situated around all sides of the inflorescence; awns straight, fine, dense, yellowish or cream color; blades flat, found in wet areas such as ditches, lakes, seeps, and streams.

NOTE: The inflorescence of Polypogon is actually a contracted panicle, not a spike. It was placed in this group because it may appear to some to be a spike or spikelike.

(6) Setaria (Foxtail)

Many species in this genus are annuals. Culms are often bent at the nodes. Awnlike bristles protrude from the rachis, giving the cylindrical inflorescence a fuzzy appearance. Spikelets are ovate in outline, and flat on one side. Ligule is a ring of hairs or membrane with hairs.

NOTE: The inflorescence of Setaria is actually a contracted panicle, not a spike. It was placed in this group because it may appear to some to be a spike or spikelike. Also, the bristles found in Setaria are not actually awns. However, since some may mistake the bristles for awns, Setaria is placed in the "awned" group. Setaria can also be found in its correct location in the "contracted panicle" group.

PANICLE/RACEME INFLORESCENCE (PANICLE/RACEME FLOWER)

Cenchrus (Sandbur)

Spikelets enclosed in a bur with rigid, thorny projections; found in open, sandy, disturbed sites.

SPIKELETS-WITH AWNS

(1) Agrostis (Bentgrass)

Spikelets small (1.5-3.5 mm long), green or often reddish-purple, awn very tiny (up to 1 mm long); ligule 2.5-7 mm long, found along waterways, in marshes, wet meadows and near seeps.

(2) Aira (Hairgrass)

Spikelets tiny, up to 2 mm long excluding awns; awns light-colored, very fine; spikelets a reddish purplish color at maturity. Edges and tips of glumes are glossy, transparent. Annuals with weak roots.

(3) Avena (Oat)

Two awns arising from each spikelet; glumes are large and papery; grass is an annual; base of seed in some species extended into a tough point; some species with hairs inside the spikelet.

(4) Bromus (Brome)

Glumes between 4-10 mm long; blades wide and flat; sheaths closed at least half their length.

(5) Dactylis (Orchardgrass)

Spikelets 5-9 mm long, grouped in dense clumps on panicle branches, 1-2 branches per node, awns up to 2 mm long.

(6) Echinochloa (Barnyardgrass/Junglerice)

Spikelets elliptical, pointed at the end, leaves broad and flat, thick culms; found on moist sites.

(7) Festuca octoflora (Sixweeks fescue/Sixweeksgrass)

Spikelets 2-7 mm long excluding awns; annuals with weak roots, plant bright green when young, drying to tan.

(8) Poa bulbosa (Bulbous bluegrass)

Stems and leaves arising from pear-shaped bulbs to about 1 cm long; spikelets small (4 mm long) excluding "awns", borne in dense clusters at the ends of .5-3 dm long branches.

(9) Polypogon (Rabbitfoot grass)

Grass without rhizomes; spikelets tiny (to 2 mm long), situated around all sides of the inflorescence; awns straight, fine, dense, yellowish or cream color; blades flat, found in wet areas such as ditches, lakes, seeps, and streams.

(10) Setaria (Foxtail)

Many species in this genus are annuals. Culms are often bent at the nodes. Awnlike bristles protrude from the rachis, giving the cylindrical inflorescence a fuzzy appearance. Spikelets are ovate in outline, and flat on one side. Ligule is a ring of hairs or membrane with hairs.

NOTE: The bristles found in Setaria are not actually awns. However, since some may mistake the bristles for awns, Setaria is placed in the "awned" group. Setaria can also be found in its correct location in the "no awns" group.

(11) Sorghum (Johnsongrass/Shattercane)

Ligule a 1.5-3 mm long membrane; large panicle; not persisting in cooler regions; often escaping culrtivation; awns readily falling off and appearing awnless.

(12) Stipa (Needlegrass)

Only one awn arising from each spikelet; base of seed extended into a tough point, usually surrounded by stiff hairs.

SPIKELETS-ROUNDED

(1) Sorghum (Johnsongrass/Shattercane)

Spikelets elliptical or rounded; no bristles from rachis; Ligule a membrane

(2) Echinochloa (Barnyardgrass/Junglerice)

Spikelets elliptical or rounded; no bristles from rachis; No ligule present

(3) Panicum (Guineagrass/Panicum/Millet/Torpedograss/Witchgrass/Maidencane)

Spikelets elliptical or rounded; no bristles from rachis; Ligule a ring of hairs

(4) Setaria (Foxtail)

POINTED SPIKELETS

(1) Agrostis exarata (Spike Bentgrass)

Spikelets small (1.8-4 mm long), green or sometimes purple-tinged; awnless or with a very tiny awn (to 5 mm long); ligule 3-14 mm long membrane; found along waterways, in marshes, wet meadows and near seeps.

(2) Agrostis stolonifera (Redtop/Carpet Bentgrass)

Spikelets small (1.5-3.5 mm long), green or often reddish-purple; awnless or awn very tiny (up to 1 mm long); ligule 2.5-7 mm long; panicle 4-40 cm long and 1-15 cm wide; found along waterways, in marshes, wet meadows and near seeps.

(3) Bromus inermis (Smooth brome), with "W" on leaf

Leaf blade with a single constriction running across the width of the leaf, forming a "W" shape.

(4) Dactylis glomerata (Orchardgrass)

Spikelets 5-9 mm long, grouped in dense clumps on panicle branches, 1-2 branches per node; ligule a 2.5-11 mm long membrane; awnless or awns to 2 mm long. Found in disturbed sites, widely distributed in temperate and cold portions of Europe and Asia; found worldwide.

(5) Eragrostis cilianensis (Stinkgrass)

Unpleasantly scented; long hairs present at summit of sheath (base of blade); ligule a ring of hairs; panicle open; 1-20 cm long and 1-7 cm wide; pale to dark gray green. Native to Eurasia, introduced in Canada and widespread throughout the U. S., in northern Mexico; Central and South America.

(6) Leptochloa filiformis (Sprangletop)

Panicle often 1/3 to 1/2 the height of the plant; spikelike branches 2-15 cm long; spikelets tiny (1.5-3.5 mm long); most often reddish purple; sheath often with soft hairs; found on wet sites. Found in southeastern U. S. east through Texas to Mississippi; rare in the eastern U. S.; Mexico; South America.

(7) Phalaris (Canarygrass)

Grass from moist sites; inflorescence oval shaped; spikelets pale with vibrant green stripes.

(8) Poa (Bluegrass)

Blade tips often prow-shaped. In many species, when the spikelet is pulled apart, cottony fibers can be found at the base of the floret. Found in temperate and cold regions of the world, extending into the subtropics and tropics as cool-season and as montane grasses.

(9) Poa bulbosa (Bulbous bluegrass)

Stems and leaves arising from pear-shaped bulbs to about 1 cm long; spikelets small (to 4 mm long), borne in dense clusters at the ends of .5-3 dm long branches.

GRASS-LIKE: SEDGES/RUSHES

Cyperaceae

  (1) Cyperus compressus (Annual nutsedge)

  (2) Cyperus esculentus (Yellow nutsedge)

  (3) Cyperus rotundus (Purple nutsedge)

  (4) Eleocharis (Spikerush)

BROADLEAF WEEDS

Broadleaf Weed Crop Pests

Alternate Leaves

(Leaves alternate up the stem)

Heart Shaped

(Leaf shaped like a heart.)

No obvious flower; only a bur

Xanthium strumarium (Common/Heartleaf cocklebur) 

This is an annual plant with purple mottled stems. It grows to a height of 2-10 dm. Fruit is a 1-3 cm long, woody bur. The bur is covered in hooked spines, with two curved spines at the tip.

Petals pink or purplish

Arcticum (Burdock) 

This is a biennial plant that grows from a taproot. The first year the plant produces only a basal rosette of leaves. The flowering stalks are produced only in the second year. The basal leaves are similar to rhubarb leaves and are thinly or thickly hairy. Flower petals are pink or purplish, and are surrounded by a green, bristly, burlike structure. Flowers arise in the leaf axils and at the ends of the branches.

Petals yellow

Abutilon theophrasti (Velvetleaf) =====

This is an annual plant with robust stems. It grows from 5-15 dm tall and is covered with short, velvety hairs. Petals are yellow-orange, 6-12 mm long. The fruit is a squat, cylindric capsule with 9-15 divisions. Each division has a short spur bending outward at the top of the fruit.

Elliptical/ovate

No obvious flower; only a bur

Xanthium strumarium(Common/Heartleaf cocklebur) 

This is an annual plant with purple mottled stems. It grows to a height of 2-10 dm. Fruit is a 1-3 cm long, woody bur. The bur is covered in hooked spines, with two curved spines at the tip.

Inconspicuous flower; no bur

Eremocarpus setigerus (Turkey Mullein) =====

This is a low annual that grows from a taproot. The plant is grayish and fuzzy with star shaped, stinging hairs. Branches are repeatedly forked in pairs. Leaves are all rounded, and have three veins from the leaf base. Two kinds of inconspicuous flowers are found in axils and at branch ends.

Petals pink or purple

Arcticum (Burdock) 

This is a biennial plant that grows from a taproot. The first year the plant produces only a basal rosette of leaves. The flowering stalks are produced only in the second year. The basal leaves are similar to rhubarb leaves and are thinly or thickly hairy. Flower petals are pink or purplish, and are surrounded by a green, bristly, burlike structure. Flowers arise in the leaf axils and at the ends of the branches.

Malva (Mallow) 

The problem species of this genus are most often annual or biennial and grow from taproots. Stems can grow along the ground or erect. Leaves are rounded and have wavy or shallowly lobed edges. Flower petals are fused together to form a cup-like shape. The petals are most often white, with faint, lavender stripes. The fruit is button-like, about .5 to 1 cm across.

Petals white

Arcticum (Burdock) 

This is a biennial plant that grows from a taproot. The first year the plant produces only a basal rosette of leaves. The flowering stalks are produced only in the second year. The basal leaves are similar to rhubarb leaves and are thinly or thickly hairy. Flower petals are pink or purplish, and are surrounded by a green, bristly, burlike structure. Flowers arise in the leaf axils and at the ends of the branches.

Malva (Mallow) 

The problem species of this genus are most often annual or biennial and grow from taproots. Stems can grow along the ground or erect. Leaves are rounded and have wavy or shallowly lobed edges. Flower petals are fused together to form a cup-like shape. The petals are most often white, with faint, lavender stripes. The fruit is button-like, about .5 to 1 cm across.

Lanceolate

Petals blue

Cichorium intybus (Chicory) 

This is a perennial plant that grows from 3-10 dm tall. It has milky juice. There are 1-3 flower heads per node along the stem. The flower heads have no flower stalk, or a very short flower stalk, so that they are clustered right against the stem.

Lactuca pulchella (Blue Lettuce) 

This is a perennial plant that grows to 2 m tall. It has milky juice. The flower heads are 2-3 cm wide from petal tip to petal tip.

Petals green or inconspicuous

(1) Amaranthus (Pigweed) 

Members of this genus are annuals. Stems can be green or are often reddish. Stems often have light striping. Flowers are borne in dense clusters from wing axils and at stem ends. Each cluster has 3 bracts at its base. Bracts are between 2-6 mm long. Bracts vary in color from green to red or purple. Bract shape can be so narrow as to appear bristle-like, or just wide enough to look like an elongate, narrow leaf. Members of this genus look similar to members of the genus Chenopodium. Amaranthus species have bracts below each flower cluster. Chenopodium members have no such bracts.

(2) Chenopodium (Goosefoot/Lambsquarter) 

Members of this genus are annuals. Stems often have light striping. Flowers are borne in dense clusters in leaf axils and at stem ends. Members of this genus look similar to members of the genus Amaranthus. Amaranthus species have bracts below each flower cluster. Chenopodium members have no such bracts.

(3) Croton californicus (Mojave Croton) 

This is a perennial plant that grows from a taproot. It grows from 2-10 dm tall. The top of the leaf appears more greenish than the underside of the leaf. The underside of the leaf appears grayish or silvery. This grayish color is due to many stellate hairs. The flower has no petals, but may appear yellow due to its 10-15 yellow stamens.

(4) Kochia scoparia (Kochia) 

This is an annual plant that grows from 3-12 dm tall. Stems are often reddish. Leaves often have short, soft hairs, especially below. Flowers are inconspicuous, borne in leaf axils. This species may look similar to members of the genus Amaranthus or Chenopodium. Kochia scoparia has narrower leaves than either of these two genera, and its flower clusters are not as dense. In addition, the green bracts appearing below K. scoparia's flower clusters are larger and more leaf-like than bracts of Amaranthus.

(5) Rumex crispus (Curly Dock) 

This is a perennial plant with a taproot. It grows from 3-10 dm tall. It has one main stalk that does not branch until the upper portion of the plant. It has small flowers which turn a reddish rust color at maturity. Individual seeds are encased in a papery, winged structure, about 3 mm long. There are several species in this genus which look similar.

(6) Salsola (Russian Thistle) 

Members of this genus are annuals which grow from a taproot. Stems of one species, S. iberica, have red-purple stripes. Plants grow to heights of 1-10 dm tall. Plants often have numerous branchings. Flowers are minute, borne in bract axils. Bracts are rigid and spiny.

Petals purple

(1) Conyza canadensis (Horseweed) 

This is an annual plant that grows from .5-10 dm tall. The leaves often fall off by the time the flowers are older. The flower heads are numerous and small, only about 4 mm high and 3-7 mm wide.

(2) Epilobium angustifolium (Fireweed) 

This is a perennial plant that grows from rhizomelike roots. At least the upper stem is often purplish. Leaves can be up to 20 cm long and have no leafstalk or a very short one. Petals are 8-20 mm long.

(3) Solanum carolinense (Horsenettle) 

This is a perennial plant that grows from underground rhizomes. It grows from 3-10 dm tall, has small spines and hairs throughout the plant. Leaves have spines along the main veins, and are borne on a leaf stalk up to 3 cm long. The flower is 2-3 cm wide. The berry is yellow at maturity.

(4) Solanum nigrum (Black Nightshade) 

This is an annual plant with slender, many-branched stems. It has few or no hairs. The flowers grow in clusters, with all the flower stalks of a cluster departing from the same point on the plant (an umbel). Each flower cluster has 2-4 flowers. The berry is black.

(5) Tragopogon porrifolius (Common Salsify) 

This is a biennial plant with milky juice. It grows from 3-10 dm tall. There are between 5-11 (commonly 8) green bracts surrounding the purple petals. The petals are as long as or slightly shorter than the green bracts. This plant is found on canal banks, in moist meadows, and along roadsides. It is widespread in much of the U. S. and is introduced from Europe.

(6) Veronia marginata (Ironweed) 

This is a perennial plant that grows from 3-7 dm tall. The stem is single, not branching until the upper portion of the plant. There are many leaves along the stem. They have no leaf stalk or only a very short leaf stalk, so the leaf blade grows directly from the stem. The underside of the leaf has minute dots. The scale-like bracts surrounding the petals are greenish-purple.

Petals rose or pink

(1) Epilobium angustifolium (Fireweed) 

This is a perennial plant that grows from rhizomelike roots. At least the upper stem is often purplish. Leaves can be up to 20 cm long and have no leafstalk or a very short one. Petals are 8-20 mm long.

(2) Polygonum coccineum (Swamp Smartweed)

This is a perennial plant with rhizomes or stolons. It is both aquatic and terrestrial. In water, stems often float. On land, stems can be erect. The flowering portion of the plant is spikelike, growing at the ends of the stems. The flowering portion is 1-8 cm long.

(3) Polygonum persicaria (Ladysthumb)

This is an annual plant that grows from a taproot. It is found in moist sites but is not aquatic. A purple splotch is often found at the center of each leaf. Transparent, membranous bracts, 5-15 mm long, encircle the stem at each node. Flowers are borne in spikelike clusters from the axils and on the terminal portion of the stem.

(4) Veronia marginata (Ironweed)

This is a perennial plant that grows from 3-7 dm tall. The stem is single, not branching until the upper portion of the plant. There are many leaves along the stem. They have no leaf stalk or only a very short leaf stalk, so the leaf blade grows directly from the stem. The underside of the leaf has minute dots. The scale-like bracts surrounding the petals are greenish-purple.

Petals white

(1) Aster ericoides (Heath Aster) 

This is a perennial plant that grows from extensive rhizomes and stolons. It grows to a height of 5-10 dm. Many of the leaves fall before flowering time. Flower heads are numerous and grow mostly from one side of the stem. Petals are up to 6 mm long.

(2) Camelina microcarpa (Falseflax) 

Members of this genus are annuals. The root is a taproot. Leaves grow directly from the stem and clasp around it. The sepals are about 2 mm long and are often reddish. Petals are 3-4 mm long. Fruits are about 5 mm long, 4 mm wide. They are rounded at the top and narrow to a point at the bottom.

(3) Cardaria draba (Whitetop/Hoary Cress) 

This is a rhizomatous perennial that is 1.5-6 dm tall. Leaf bases clasp around the stem. Petals are 2-4 mm long. Fruit is disk-shaped, 2-4 mm long, 4-6 mm wide.

(4) Chrysanthemum leucanthemum (Oxeye Daisy) 

This is a rhizomatous, perennial plant that grows to a height of 2-10 dm. The central disk of the flower head is 10-20 mm across. There are 15-30 outer petals. Each is 10-20 mm long.

(5) Conyza canadensis (Horseweed) 

This is an annual plant that grows from a taproot. It grows to a height of 3-15 dm. The flower head is up to 4 mm tall.

(6) Lepidium (Pepperweed) 

Many members of this genus are annuals. The root is a taproot. The leaves are often without leafstalks, so the leaf grows directly from the stem. In some species, the leaf bases clasp around the stem. The green sepals surrounding the white petals are 1-2 mm long. The petals are .5-3 mm long. The fruits are flattened and rounded in outline. Fruits are between 2.5-6 mm long.

(7) Oenothera biennis (Common Eveningprimrose) 

This plant usually has a lifespan of two years. It usually has only one stem, and grows to be 3-12 dm tall. The leaves at the plant base have leafstalks, but leafstalks become progressively shorter upward. The sepals are 1-2 cm long and flex backwards from the petals. The yellow petals are 1-2 cm long. Older petals may turn whitish or orange. The fruit is a capsule which grows to 1.8-4 cm long. The plant is found in moist, disturbed sites.

(8) Polygonum aviculare (Prostrate Knotweed) 

This is an annual plant that grows from a taproot. It can grow erect or flat on the ground. The stems are lightly striped and can be round or angled in cross-section. Stems reach lengths from 1-10 dm. Leaves are smaller on the branchlets than on the main stem. Flowers are only 2-3 mm long and are whitish or pinkish.

(9) Polygonum persicaria (Ladysthumb) 

This is an annual plant that grows from a taproot. It is found in moist sites but is not aquatic. Papery bracts, 5-15 mm long, encircle the stem at each node. Flowers are borne in spikelike clusters from the axils and on the terminal portion of the stem.

(10) Solanum carolinense (Horsenettle) 

This is a perennial plant that grows from creeping underground rhizomes. It grows from 3-10 dm tall, and has small spines and hairs throughout the plant. Leaves have spines along the main veins, and are borne on a leaf stalk up to 3 cm long. The flower is 2-3 cm wide. The berry is yellow at maturity.

(11) Solanum ptychanthum (Black Nightshade) 

This is an annual plant that grows from a taproot. It grows from 3-6 dm tall and has no or few hairs. If hairs are present, they are most dense on young leaves and stems. The flowers grow in clusters of 3 or 4, with all the flower stalks of a cluster departing from the same point on the plant (an umbel). The flower petals are 4-7 mm long. The mature berry is purplish-black.

(12) Thlaspi (Pennycress) 

Many members of this genus are annuals. The root is a taproot. Leaves are without leafstalks, so the leaf grows directly from the stem. Leaves are larger towards the base than at the top. Leaves at the top clasp around the stem. The green sepals surrounding the white petals are 1.5-2.5 mm long. The petals are 3-4.5 mm long. The fruits are flat and rounded in outline and are 10-17 mm long, 7-12 mm wide.

Petals yellow or orange

(1) Amsinckia (Fiddleneck) 

This is an annual plant that grows from 3-9 dm tall. It has coarse bristles throughout the plant. The flowers are yellow-orange and grow close to the stem and are 5-10 mm long. The flowering portion of the stem curls under towards the end.

(2) Brassica campestris (Wild Turnip) 

This is an annual plant that grows to 2.5-10 dm tall. Petals are yellow and 6-10 mm long. The fruit is long and slender, between 3-7 cm long. A similar species is Brassica kaber. Brassica campestris has no or very few hairs, while Brassica kaber has hairs, especially at the base of the plant. They can with the naked eye as small white hairs if one looks closely.

(3) Brassica kaber (Charlock) 

This is an annual plant that grows to 3-10 dm tall. Petals are yellow and 8-14 mm long. The fruit is long and slender, between 3-5 cm long. A similar species is Brassica campestris. Brassica campestris has no or very few hairs, while Brassica kaber has hairs, especially at the base of the plant. They can with the naked eye as small white hairs if one looks closely.

(4) Grindelia squarrosa (Curlycup Gumweed) 

This plant lives two or more years and grows to a height of 1-8 dm tall. The plant secretes a sticky resin that can be felt by pinching the plant, especially the flower heads. There are many rows of small, green bracts surrounding the yellow petals. The tips of these bracts curl outward.

(5) Helenium amarum (Bitter Sneezeweed) 

This is an annual plant that grows from a taproot. The plant is 1-4 dm tall. Light stripes extend up the stems. Leaves are numerous and are so narrow as to be threadlike. The green bracts surrounding the yellow petals bend backwards when the flower is mature.

(6) Iva axillaris (Marshelder) 

This perennial plant grows from elongate rhizomes. It reaches heights between 15-50 cm tall. Leaves are opposite at the base of the plant and alternate at the top of the plant. There are numerous (100s) of flower heads clustered around the stems.

(7) Linaria vulgaris (Toadflax) 

This is a perennial plant that grows from creeping roots. It grows from 2.5-6.8 dm tall. Flowers grow close together along the stem and are 13-17 mm long. They are bright yellow with an orange portion in the center of the flower. A 10-12 mm long yellow spur extends downward from the flower.

(8) Lithospermum incisum (Gromwell) 

This is a perennial plant that has several stems growing from a thick woody root. Its height is between 1-5 dm. Yellow flowers are clustered at the ends of the stems, and are 10-30 mm long. Each flower produces 4 white, shiny nutlets which are about 3 mm long.

(9) Oenothera biennis (Common Eveningprimrose) 

This plant usually has a lifespan of two years. It usually has only one stem, and grows to be 3-12 dm tall. The leaves at the plant base have leafstalks, which become progressively shorter upward. The sepals are 1-2 cm long and flex backwards from the petals. The yellow petals are 1-2 cm long. Older petals may turn whitish or orange. The fruit is a capsule which grows to 1.8-4 cm long. The plant is found in moist, disturbed sites.

(10) Oenothera laciniata (Cutleaf Eveningprimrose) 

This plant grows to 1-7 dm high. Leaves are between 2-10 cm long. The four sepals are much shorter than the petals, and flex backwards from the petals. Petals are yellow and 5-12 mm long. The fruit is a long, thin capsule which is 2-3 cm long. This plant grows in dry, mostly sandy places.

(11) Senecio serra (Groundsel) 

This is a perennial plant that grows to a height of 4-15 dm tall. The green bracts that surround the yellow petals are 4-11 mm high. These bracts number 8-13. There is one row of large, green bracts. Surrounding this main set of bracts is another set of tiny, short bracts. Petals are 3-10 mm long.

(12) Solidago canadensis (Canada Goldenrod) 

This perennial plant grows to 3-12 dm tall. The basal leaves are withered by the time the plant flowers. Leaves along the stems are longer than the internodes. Leaves are alternate all the way up the stem. The yellow flower heads are borne in clusters, mostly at the tops of the stems. The flowering portion of the stem often curves over on itself.

(13) Sonchus uliginosus (Sowthistle) 

This is a perennial plant with rhizomelike roots. Leaf bases clasp around the stem and have prickly edges. The green bracts surrounding the yellow petals are 14-16 mm high. Petals are 10-20 mm long.

(14) Tragopogon pratensis (Meadow Salsify) 

This plant has a lifespan of two years. Stems are 1.5-8 dm tall. The green bracts surrounding the yellow petals usually number 8. Petals are equal in length to these bracts or slightly longer. The plant has milky juice.

(15) Verbascum thapsus (Common Mullein) 

This is a biennial plant with stout stems that grow from 5-15 dm tall. The first year the plant grows only as a basal rosette. The plant sends up a flowering stalk the second year. The whole plant is densely woolly. The yellow flowers grow close to the stem and are somewhat overlapped by the small leaves of the upper stem.

Lobed or compound

Petals blue

(1) Delphinium (Larkspur) 

Members of this genus vary in their lifespans, height and in their herbage. However, they are similar in some respects. Their stems are erect and rarely branched. Their leaves are palmately divided (veins all radiating from a central point). Flowers are large (about 1-3 cm across), asymmetrical and showy, usually purple or blue, but sometimes white. Flowers have a spur that is usually at least as long as the rest of the flower.

(2) Lactuca serriola (Prickly Lettuce)                              

This is an annual plant that grows from a taproot. It has milky juice and grows to height from 3-18 dm tall. Branching occurs only in the flowering portion. Leaves are from 3-30 cm long, and are twisted at the base so that they are vertically oriented. The main vein on the underside of the leaf has prickles. Each flower head is about 1 cm across.

(3) Lupinus (Lupine) 

Members of this genus are usually perennials but some are annuals. Leaves are palmately compound, with 6-8 leaflets originating at a central point. Flower shape is similar to that of a pea plant. Flower color varies from blue to purple to white. Flowers are borne along the top portion of the stem, maturing from the bottom upwards. Fruit is a hairy pod. Most members of this genus contain poisonous alkaloids which can harm or kill livestock.

(4) Medicago sativa (Alfalfa) 

This is a perennial plant with a taproot that grows from 4-12 dm long. Leaves are pinnately compound, and have three leaflets. Each leaflet has tiny teeth on its edges. Teeth do not extend further than one-third back from the leaflet tip. Flowers are small (6-10 mm long) and are found in groups of 6-25 on each flowering stalk. The fruit is a small pod which is spirally coiled.

No obvious flower; green or inconspicuous

(1) Ambrosia artemisiifolia (Common Ragweed) 

This is an annual plant that grows from 3-9 dm tall. It branches above the middle of the plant. Flower heads are numerous and grow on flower stalks from branch ends. Lower leaves are usually opposite, while upper leaves are alternate. Flower heads are from 3-7 mm across, and do not have ray flowers. The cup-like structure below the petals appears green rather than grayish.

(2) Artemisia vulgaris (Mugwort) 

This is a perennial plant that grows from .5-2 m tall. Leaves are green on the upper side, and have dense, white, fuzzy hairs on the underside. The leaf is often dissected into smaller leaflets. Flower heads are from 3-7 mm across, and are crowded onto elongate flowering stalks. There are no ray flowers. The flowers have a grayish appearance due to the grayish cup that is just below the petals.

(3) Xanthium strumarium (Common Cocklebur/Heartleaf Cocklebur) 

This is an annual plant with purple mottled stems. It grows to a height of 2-10 dm. Fruit is a 1-3 cm long, woody bur. The bur is covered in hooked spines, with two curved spines at the tip.

Petals pink

(1) Achillea millefolium (Yarrow) 

This is a perennial plant which grows from horizontal rhizomes. Stems have hair and reach heights of .5-10 dm. Stems do not branch until the upper portion of the plant. Flower heads are numerous, aromatic, and are borne in clumps at the ends of branches. Leaves are finely dissected.

(2) Capsella bursa-pastoris (Shepherd's Purse) 

This plant is an annual and is 1-5 dm tall. Basal leaves are usually lobed, and are 2-16 cm long. Leaves on the upper plant are smaller and clasp around the stem. Flowers are small (2-4 mm long). Fruits are heart-shaped and have a ridge down each side.

(3) Centaurea maculosa (Knapweed) 

This plant is a biennial or short-lived perennial from a taproot. It reaches heights from 3-10 dm. It usually only starts branching above the middle. Flower heads grow singly at the ends of branches. Petals are curve out to form a saucer shape. Petals are borne on top of bracts which form a green cup-like structure. Each bract is dark-tipped.

(4) Malva (Mallow) 

The problem species of this genus are most often annual or biennial and grow from taproots. Stems can grow along the ground or erect. Leaves are rounded and have wavy or shallowly lobed edges. Flower petals are fused together to form a cup-like shape. The petals are most often white, with faint, lavender stripes. The fruit is button-like, about .5 to 1 cm across.

(5) Medicago sativa (Alfalfa) 

This is a perennial plant with a taproot that grows from 4-12 dm long. Leaves are pinnately compound, and have three leaflets. Each leaflet has tiny teeth on its edges. Teeth do not extend further than one-third back from the leaflet tip. Flowers are small (6-10 mm long) and are found in groups of 6-25 on each flowering stalk. The fruit is a small pod which is spirally coiled.

(6) Trifolium repens (White Clover) 

This is a perennial that grows from 8-35 cm tall. Stems are stoloniferous, creeping and rooting at the nodes. Flower stalks often arise at right-angles to the stem axis. Flowers are small (from 5-10 mm long) and are clustered in globose heads. Each flower head is about 10-30 mm in diameter. Flowers are white or pinkish and fade brown.

Petals purple or lavender

(1) Achillea millefolium (Yarrow) 

This is a perennial plant which grows from horizontal rhizomes. Stems have hair and reach heights of .5-10 dm. Stems do not branch until the upper portion of the plant. Flower heads are numerous, aromatic, and are borne in clumps at the ends of branches. Leaves are finely dissected.

(2) Centaurea maculosa (Knapweed) 

This plant is a biennial or short-lived perennial from a taproot. It reaches heights from 3-10 dm. It usually only starts branching above the middle. Flower heads grow singly at the ends of branches. Petals are curve out to form a saucer shape. Petals are borne on top of bracts which form a green cup-like structure. Each bract is dark-tipped.

(3) Cirsium arvense (Canada Thistle) 

This is a rhizomatous perennial that grows from 5-10 dm tall. The green, cup-shaped structure below the petals is 10-20 mm high and 10-25 mm wide. The bracts forming this structure have no spines.

(4) Cirsium vulgare (Bull Thistle) 

This is a biennial plant that grows from 3-12 dm tall. A basal rosette is produced the first year of its life. A flowering stalk is not produced until the second year of its life. Leaves have fuzzy hair beneath, and coarse hairs above. The green, cup-shaped structure below the petals is 3-4 cm high and 3.5-7 cm wide. The bracts forming this stucture have spines that bend outward.

(5) Delphinium (Larkspur) 

Members of this genus vary in their lifespans, height and in their herbage. However, they are similar in some respects. Their stems are erect and rarely branched. Their leaves are palmately divided (veins all radiating from a central point). Flowers are large (about 1-3 cm across), asymmetrical and showy, usually purple or blue, but sometimes white. Flowers have a spur that is usually at least as long as the rest of the flower.

(6) Fumaria officinalis (Fumitory) 

This is an annual plant that grows erect or sprawls. Stems grow from 1.5-6 dm tall. Leaves have fine divisions. Flowers are 5-10 mm long and have a tiny spur. Flowers are few to numerous and grow in clusters from axils. Flower tips are darker than the rest of the flower body.

(7) Lupinus (Lupine) 

Members of this genus are usually perennials but some are annuals. Leaves are palmately compound, with 6-8 leaflets originating at a central point. Flower shape is similar to that of a pea plant. Flower color varies from blue to purple to white. Flowers are borne along the top portion of the stem, maturing from the bottom upwards. Fruit is a hairy pod. Most members of this genus contain poisonous alkaloids which can harm or kill livestock.

(8) Medicago sativa (Alfalfa) 

This is a perennial plant with a taproot that grows from 4-12 dm long. Leaves are pinnately compound, and have three leaflets. Each leaflet has tiny teeth on its edges. Teeth do not extend further than one-third back from the leaflet tip. Flowers are small (6-10 mm long) and are found in groups of 6-25 on each flowering stalk. The fruit is a small pod which is spirally coiled.

(9) Vicia sativa (Common Vetch) 

This Vicia species is similar to Vicia villosa, except that V. sativa has larger flowers, leaves and pods.

(10) Vicia villosa (Hairy Vetch) 

This is an annual plant that grows from 5-20 dm tall. Stems are hairy. Leaves are pinnately compound with 10-18 leaflets. The leaf tip ends in tendrils. Flowers are about 16 mm long. Flowers are clustered along a flowering stalk, 20-60 flowers per cluster, and are usually all growing from one side of the stem. The fruit is a pod, 20-30 mm long.

Petals reddish or violet

(1) Pastinaca sativa (Wild Parsnip) 

This is an aromatic, biennial plant that grows from a large taproot. It grows from 8-15 dm tall. Leaves are 12-35 cm long, and are divided into small leaflets which are opposite from each other. There are usually between 6-15 flower clusters on the plant. In each cluster, the flower stalks depart from the same point on the plant (an umbel). Flowers are small.

(2) Datura stramonium (Jimsonweed) 

This is an annual plant with stems from 3-10 dm tall. It has large leaves from 1-2 dm long. Flowers are trumpet-shaped, 5-11 cm long. Flowers are found in the stem axils. Fruits are oval in shape and are covered with rigid prickles.

(3) Vicia villosa (Hairy Vetch) 

This is an annual plant that grows from 5-20 dm tall. Stems are hairy. Leaves are pinnately compound with 10-18 leaflets. The leaf tip ends in tendrils. Flowers are about 16 mm long. Flowers are clustered along a flowering stalk, 20-60 flowers per cluster, and are usually all growing from one side of the stem. The fruit is a pod, 20-30 mm long.

(4) Fumaria officinalis (Fumitory) 

This is an annual plant that grows erect or sprawls. Stems grow from 1.5-6 dm tall. Leaves have fine divisions. Flowers are 5-10 mm long and have a tiny spur. Flowers are few to numerous and grow in clusters from axils. Flower tips are darker than the rest of the flower body.

Petals white

(1) Achillea millefolium (Yarrow) 

This is a perennial plant which grows from horizontal rhizomes. Stems have hair and reach heights of .5-10 dm. Stems do not branch until the upper portion of the plant. Flower heads are numerous, aromatic, and are borne in clumps at the ends of branches. Leaves are finely dissected.

(2) Anthemis arvensis (Corn Chamomile) 

This is a bushy annual plant that grows from 1-3 dm tall. It has a mild, pleasant scent. Each leaf is 2-5 cm long, with numerous divisions. The midvein of the leaf has narrow wings. The yellow portion of the flower head is 7-12 mm across. Each of the white rays is 15-20 mm long.

(3) Capsella bursa-pastoris (Shepherd's Purse) 

This plant is an annual and is 1-5 dm tall. Basal leaves are usually lobed, and are 2-16 cm long. Leaves on the upper plant are smaller and clasp around the stem. Flowers are small (2-4 mm long). Fruits are heart-shaped and have a ridge down each side.

(4) Cicuta maculata (Waterhemlock) 

This is a violently poisonous, perennial plant which reaches heights from 6-21 dm tall. Its roots are fibrous, with a thickened crown. When split, this thickened portion reveals horizontal chambers. This root portion is the most poisonous part and should be handled with extreme caution. Leaves are pinnately divided. Flowers are small and borne in clusters in an umbel.

(5) Cirsium undulatum(Gray Thistle) 

This is a perennial plant that grows from a taproot and is between 2-10 dm tall. Leaves of the basal rosette reach lengths of 7-25 cm long and have fuzzy hair on both sides. The green, spiny cup underneath the petals is between 2-3 cm high and 2-6 cm wide. The bracts forming the cup often have a white stripe up the center.

(6) Datura stramonium (Jimsonweed) 

This is an annual plant with stems from 3-10 dm tall. It has large leaves from 1-2 dm long. Flowers are trumpet-shaped, 5-11 cm long. Flowers are found in the stem axils. Fruits are oval in shape and are covered with rigid prickles.

(7) Descurainia (Tansy) 

Members of this genus are annuals, or biennials which grow from taproots. They reach heights of 1-14 dm. Leaves are narrowly dissected. Petals are small (about 3 mm long), and are yellow or white in color. Fruits are narrow, elongate, dry pod-like structures. They reach lengths between 5-30 mm.

(8) Eupatorium (Dogfennel/Mayweed) 

(9) Malva (Mallow) 

The problem species of this genus are most often annual or biennial and grow from taproots. Stems can grow along the ground or erect. Leaves are rounded and have wavy or shallowly lobed edges. Flower petals are fused together to form a cup-like shape. The petals are most often white, with faint, lavender stripes. The fruit is button-like, about .5 to 1 cm across.

(10) Medicago sativa (Alfalfa) 

This is a perennial plant with a taproot that grows from 4-12 dm long. Leaves are pinnately compound, and have three leaflets. Each leaflet has tiny teeth on its edges. Teeth do not extend further than one-third back from the leaflet tip. Flowers are small (6-10 mm long) and are found in groups of 6-25 on each flowering stalk. The fruit is a small pod which is spirally coiled.

(11) Melilotus (Sweetclover) 

Plants in this genus are annuals or biennials that grow from a taproot. Plants reach heights from 5-15 dm tall. Leaves are pinnately compound, with three leaflets. Leaflet edges have tiny teeth at least to halfway back on the leaf, sometimes around the whole leaflet. Flowers are numerous. Flowers are arranged around a flower stalk that grows from axils and from branch ends.

(12) Raphanus (Radish) 

Members of this genus are annuals. Basal leaves are divided into lobes, with the lobe at the tip being largest. The bracts (sepals) encircling the petals are green to reddish or purplish. Petals are 12-20 mm long. R. sativus has white to purplish flowers with pinkish veins, while R. raphanistrum has yellow flowers with dark veins.

(13) Sisymbrium officinale (Hedge Mustard) 

This is an annual plant that grows to heights of 3-8 dm tall. Leaves are between 1-20 cm long. The basal and upper leaves are the same shape, but the basal leaves are larger. The flowers are small, with petals about 4 mm long. Petals are yellow but fade white. The fruit is narrow and elongate, 8-15 mm long.

(14) Solanum sarrachoides (Hairy Nightshade) 

This is an annual plant. Its stems grow from 1-5 dm long. Leaves and stems are hairy. The plant may feel sticky to the touch. The flower is white, 3-5 mm wide and has a yellow center. The berry is 6-7 mm wide and yellow when ripe. The green calyx cups the bottom half of the berry,

(15) Trifolium repens (White Clover) 

This is a perennial that grows from 8-35 cm tall. Stems are stoloniferous, creeping and rooting at the nodes. Flower stalks often arise at right-angles to the stem axis. Flowers are small (from 5-10 mm long) and are clustered in globose heads. Each flower head is about 10-30 mm in diameter. Flowers are white or pinkish and fade brown.

Petals yellow

(1) Anthemis arvensis (Corn Chamomile) 

This is a bushy annual plant that grows from 1-3 dm tall. It has a mild, pleasant scent. Each leaf is 2-5 cm long, with numerous divisions. The midvein of the leaf has narrow wings. The yellow portion of the flower head is 7-12 mm across. Each of the white rays is 15-20 mm long.

(2) Barbarea (Yellow Rocket) 

Members of this genus are usually biennials or perennials. Stems are erect and up to 1 m tall. Basal leaves are divided into thin lobes, with a large, rounded lobe at the leaf tip. Leaves become smaller upwards and clasp onto the stem. Flower petals are about .5 cm long. Flowers grow in clusters at stem tips.

(3) Brassica (Wild Turnip) 

Members of this genus are annuals that grow from taproots. Leaves are variously shaped even within a species. Basal leaves are often divided, and leaves higher on the stem are often unlobed. Flower petals are between about .5-1 cm long. Fruits are elongate, pod-like structures, between 2-7 cm long, and are round in cross section.

(4) Centaurea solstitialis (Yellow Starthistle) 

This species is an annual or biennial with fuzzy, grayinsh hair and winged stems. It grows to heights of 1-6 dm tall. Flower heads are found on branch ends. The cup-shaped structure below the petals has long, stout spines that are from 10-20 mm long.

(5) Descurainia (Tansy) 

Members of this genus are annuals, or biennials which grow from taproots. They reach heights of 1-14 dm. Leaves are narrowly dissected. Petals are small (about 3 mm long), and are yellow or white in color. Fruits are narrow, elongate, dry pod-like structures. They reach lengths between 5-30 mm.

(6) Lactuca serriola (Prickly Lettuce) 

This is an annual plant that grows from a taproot. It has milky juice and grows to height from 3-18 dm tall. Branching occurs only in the flowering portion. Leaves are from 3-30 cm long, and are twisted at the base so that they are vertically oriented. The main vein on the underside of the leaf has prickles. Each flower head is about 1 cm across.

(7) Lotus corniculatus (Birdsfoot Trefoil) 

This is an annual plant with stems from 1-5 dm long. Stems can lie flat on the ground or ascend upward. Each leaf has three leaflets. Each leaflet is rounded and widest at the tip, tapering to a point at the base. Flowers are about 1 cm long. The fruit is an elongate pod, 2-3.5 cm long. This plant is found in moist pastures.

(8) Matricaria matricarioides (Pineappleweed) 

This is an annual plant which grows up to 2.5 dm. Leaves are narrowly divided. Flower heads are cone shaped and have no ray flowers. The cup-shaped structure below each flower head is composed of bracts with papery margins. When crushed, the plant smells like pineapple.

(9) Melilotus (Sweetclover) 

Plants in this genus are annuals or biennials that grow from a taproot. Plants reach heights from 5-15 dm tall. Leaves are pinnately compound, with three leaflets. Leaflet edges have tiny teeth at least to halfway back on the leaf, sometimes around the whole leaflet. Flowers are numerous. Flowers are arranged around a flower stalk that grows from axils and from branch ends.

(10) Oxalis corniculata (Creeping Woodsorrel) 

This is a perennial plant that grows from a taproot. Its stems grow from .5-5 dm long, and often root at the nodes. Flowers grow in clusters of 1-7 from flower stalks which depart from the same point on the plant (an umbel). Petals are 4-8 mm long. The fruit is a hairy cylinder which is from 1-2.5 cm long.

(11) Pastinaca sativa (Wild Parsnip) 

This is an aromatic, biennial plant that grows from a large taproot. It grows from 8-15 dm tall. Leaves are 12-35 cm long, and are divided into small leaflets which are opposite from each other. There are usually between 6-15 flower clusters on the plant. In each cluster, the flower stalks depart from the same point on the plant (an umbel). Flowers are small.

(12) Potentilla recta (Sulfur Cinquefoil) 

This is a perennial plant that grows from 2.5-3.5 dm. Leaves are palmately divided into 5-7 toothed leaflets. Leaves may have hairs on the underside, but do not look silvery. Flowers are light yellow and have five petals.

(13) Ranunculus acris (Tall Buttercup) 

This is a perennial that grows from 2-5 dm tall. Stems are hairy. Flowers are about 2.5 cm in diameter, and have five petals. Each petal is about 8-10 mm long.

(14) Raphanus (Radish) 

Members of this genus are annuals. Basal leaves are divided into lobes, with the lobe at the tip being largest. The bracts (sepals) encircling the petals are green to reddish or purplish. Petals are 12-20 mm long. R. sativus has white to purplish flowers with pinkish veins, while R. raphanistrum has yellow flowers with dark veins.

(15) Senecio (Groundsel) 

Members of this genus vary in lifespan. Flower heads often grow in clusters at the ends of the stems. The flower head itself is surrounded by one or two rows of green bracts. The the bracts in the row closest to the petals is the longest, and are all of the same length. Bracts in this row generally number between 8-21. If present, the outer row is usually much shorter than the inner row. The rays on each head in most species number between 7-13, but in some species as few as 3 (or none) to as many as 17. The flower head generally spans from .5 cm (in species without rays) to between 1-2.5 cm in species with rays.

(16) Sisymbrium irio (London Rocket) 

This plant is a winter annual that grows from 2-8 dm tall. Leaves are borne on leafstalks that are about .5-1 cm long. Basal leaves are divided and are larger than upper leaves. Flowers are small, with petals only 3-4 mm long. Flowers are clustered at stem tips. The fruit is an elongate pod-like structure that grows from 2-4.5 cm long.

(17) Sisymbrium officinale (Hedge Mustard) 

This is an annual plant that grows to heights of 3-8 dm tall. Leaves are between 1-20 cm long. The basal and upper leaves are the same shape, but the basal leaves are larger. The flowers are small, with petals about 4 mm long. Petals are yellow but fade white. The fruit is narrow and elongate, 8-15 mm long.

(18) Solanum rostratum (Buffalobur) 

This is an annual plant that grows to heights up to 7 dm. Its stems, leaves, and fruits have long, straight prickles. The floweris yellow, and is about 2-2.5 cm across.

(19) Tanacetum vulgare (Tansy) 

This is an aromatic, perennial plant that grows from a rhizome. Stems are often purplish-red. The plant grows to heights of 3-10 dm. Leaves are divided into small segments. Each leaflet has tiny teeth around its edges. There are many flower heads, which grow in flat-topped, dense clusters. Flower heads are from .5-1 cm across.

Opposite Leaves

Heart Shaped

Petals all colors

(1) Asclepias syriaca (Common Milkweed) 

Plant with deep taproots. Stems 5-15 dm tall. Plant has milky juice. Leaves 1-1.5 dm long, 4-11 cm wide. Leaves have hair on the underside. Fruit is pod-like (a follicle), 7-9 cm long. (From Flora of the Rocky Mountains and Adjacent Plains, Rydberg, p.670. This species is similar to Asclepias speciosa, (Showy Milkweed). "Showy milkweed is native to North America and is common along roadsides, ditchbanks, pastures and cultivated fields. Colonies form by spreading rootstocks when the plant is not disturbed by tillage practices." (From Weeds of the West, p. 39).

(2) Glecoma hederacea (Ground Ivy) 

Fibrous roots, perennial with slender stolons or rhizomes. Stems are square, 1-4 dm long. Leaves are 1-3 cm long. Flowers are 5-6 mm long, blue violet. Established in moist disturbed habitats. Native of Eurasia, well established in the U. S. This species is poisonous to horses. (From A Utah Flora, Welsh, p. 371).

(3) Proboscidea (Devil's Claw/Unicornplant) 

Annuals. Plants grow spreading on the ground. Stems 30-80 cm long. Leaves can vary somewhat in shape. Petals are yellow, copper colored, dull white or purplish, spotted with purple or yellow. Fruit is a large pod. The pod base is oval, between 6-10 cm long. A beak extends from this pod, which splits into two curved claws upon drying. They are equal to, or a little longer than, the oval base. Range: Delaware to Colorado and California, southward to Mexico. (From A Flora of New Mexico, Hutchins p. 1856-1859).

Elliptical or oval

Petals green or inconspicuous

Urtica urens (Burning Nettle) 

This is an annual plant, which grows erect to a height of up to 6 dm. It has stinging bristles. All leaves are about the same shape. The stem is most often branched. The petals are actually white, but are so small that they appear greenish. It is a native of Europe, but is widespread over much of North America.

Petals purple, blue, or pink

(1) Asclepias speciosa (Showy Milkweed) 

This plant is a perennial and grows to 6-10 dm tall. Usually there is much soft hair on the stems and under the leaves. Flower petals are pink or rose colored. Each leaf has one major vein extending up the middle. When cut, veins exude a milky juice.

(2) Lamium amplexicaule (Henbit) 

This plant is an annual, has a square stem, and grows to 1-4 dm tall. The leaf edges have small, rounded lobes. The lower leaves have leaf stalks while the upper leaves have no leaf stalks. Flowers are 12-16 mm long and are purplish-red. The species is adventive to the U. S. from Europe and is now widely established in much of the U. S. It is found growing on disturbed sites such as lawns, fields, and roadsides. The species is considered to be poisonous to horses, cattle, and sheep.

(3) Lychnis alba (White Cockle) 

This plant is between 4-10 dm tall. The leaves at the very base of the plant have a leaf stalk, while the leaves along the main stem have no leaf stalks. The leaves on the main stem are larger at the bottom and become gradually smaller towards the top. Along the stem, there are between 4-10 pairs of leaves. The green, cup-like structure (calyx) surrounding the white or pink flower petals has between 10-20 veins and is 15-30 mm long. The whole flower is between 25-35 mm long.

(4) Prunella vulgaris (Healall) 

This plant often has rhizomes. Stems are square, 6 cm to .5 m tall. Leaves are 2-9 cm long, .7-4 cm wide. Petals are pink-purple to pink or white, 12-18 mm long. It is found in wet meadows, streamsides, and other moist sites. It is widespread in temperate North America and in Eurasia.

(5) Saponaria officinalis (Bouncingbet) 

This plant is a perennial and grows to 30-80 cm tall, forming clumps. The leaves are 3-12 cm long, .8-4 cm wide. The plant has many flowers, with white or pink petals. It is widely established in North America, introduced from Europe. It is poisonous to livestock due to the presence of saponins, the soapy substances in the juice.

(6) Vaccaria pyramidata (Cow Cockle) 

This plant is an annual and grows to be 15-80 cm tall. The leaves at the very base of the plant may have short leaf stalks, but none of the other leaves have leaf stalks. The green cup-like structure (calyx) surrounding the pink petals is five-angled, and constricted at the top. The veins in this cup-like structure are purplish or green. The wide, flat part of each petal is between 5-8 mm long, and has a tiny notch at the end.

(7) Veronica officinalis (Common Speedwell) 

This plant has creeping stems which take root at the nodes. It sends up branches which are 7.5-25 cm high. Leaves have tiny teeth around the edges and leaf stalks. Flowers are blue and grow densely on narrow, finger-like stalks which are much longer than the leaves. Flowers are 4-6 mm broad. After the flower petals fall, small heart-shaped capsules develop in their place.

Petals white

(1) Ambrosia trifida (Giant Ragweed) 

This annual plant has three to five main veins in each leaf. The veins originate from where the leaf stem meets the leaf blade, and radiate outward (palmate veination). The leaf can be with or without lobes. HELP: 1) Closeup of leaf, showing palmate veination.

(2) Lychnis alba (White Cockle) 

This plant is between 4-10 dm tall. The leaves toward the base have a leaf stem. The leaves at the very base of the plant have leaf stalks, while the leaves along the main stem have no leaf stalks. The leaves on the main stem are larger at the bottom and become gradually smaller towards the top. Along the stem, there are between 4-10 pairs of leaves. The green, cup-like structure (calyx) surrounding the white or pink flower petals has between 10-20 veins and is 15-30 mm long. The whole flower is between 25-35 mm long.

(3) Nepeta cataria (Catnip) 

Stems are square, 3-10 dm tall. Flowers are whitish, spotted with purple. Flower length is 7-12 mm long. Usually found in moist sites. Native to Europe, now widely distributed in North America.

(4) Saponaria officinalis (Bouncingbet) 

Perennial, 30-80 cm tall, forming clumps. Leaves are 3-12 cm long, .8-4 cm wide. The plant has many flowers, with white or pink petals. It is widely established in North America, introduced from Europe. This plant is poisonous to livestock due to the presence of saponins, the soapy substance in the juice.

(5) Stellaria media (Common Chickweed) 

Annual or biennial herb. The plant forms loose mats or clumps. Stems are 1-5 dm long, and can take root at the nodes. Petals are white, 2-6 mm long. Weedy plants of open sites. Widely established in North America, adventive from Eurasia.

(6) Prunella vulgaris (Healall) 

This plant often has rhizomes. Stems are square, 6 cm to .5 m tall. Leaves are 2-9 cm long, .7-4 cm wide. Petals are pink-purple to pink or white, 12-18 mm long. Found in wet meadows, streamsides, and other moist sites. Widespread in temperate North America and in Eurasia.

Petals yellow

Hypericum (St. Johnswort) 

Leaves, and often petals, are dotted with oil glands. Flower has five yellow petals. Each flower has about 3 bundles of stamens. Each bundle has many stamens (too many to count). The fruit is a capsule, between 5-10 mm long. Germination is in the spring. Flowering time is in the summer or in autumn. Can grow in nutrient-poor soil.

Lanceolate

Flowers green or inconspicuous

Urtica dioica (Stinging Nettle) 

Perennial plant with rhizomes. Stems 6-20 cm tall. Leaves are 4-18 cm long, 1-8 cm wide. Leaf edges are serrated. Plant has stinging hairs. Range: Widely distributed in North America.

Petals lavender/purple/blue

(1) Lythrum salicaria (Purple Loosestrife) 

Perennial herb with rhizomes. Stems are between 7-30 dm tall. Stems are erect and have coarse hairs. Leaves are opposite or whorled. Leaves are 2-10 cm long, 4-20 mm wide. Petals are 5-10 mm long. Found in moist sites. Introduced to the U. S. from Europe.

(2) Prunella vulgaris (Healall) 

This plant often has rhizomes. Stems square, 6 cm to .5 m tall. Leaves 2-9 cm long, .7-4 cm wide. Inflorescence 2-8 cm tall, 1-2 cm wide. Petals pink-purple to pink or white, 12-18 mm long. Found in wet meadows, streamsides, and other moist sites. Widespread in temperate North America and in Eurasia.

(3) Verbena hastata (Vervain) 

Stems 4-15 dm tall. Leaves 5-15 cm long. The lower leaves can sometimes be variously shaped. Flowering portion consisting of numerous erect, narrow (to 7 mm wide) spikes. Petals are blue, purplish or pink, about 3 mm long. Found in wet meadows, marshes and bogs. Widely distributed in the U. S. and southern Canada.

Petals white or pink

(1) Agrostemma githago (Corn Cockle) 

Green lobes extending longer than the petals. 3-9 dm tall. Many whitish hairs on the sepals. Leaves are 5-10 cm long. Petals are purple or red, spotted with black. Flowering is in July/September. Introduced to North America from Europe, found in grain fields and waste places.

(2) Asclepias speciosa (Showy Milkweed) 

Perennial, 6-10 dm tall. Usually with much soft hair on stems and under leaves. Petals pink or rose colored. Each leaf has 1 major vein extending up the middle of the leaf. When cut, veins exude a milky juice.

(3) Cerastium vulgatum (Mouse-ear Chickweed) 

Annual herb. Petals white. Stems and leaves with many hairs. Widely distributed in the U. S., naturalized from Europe.

(4) Melandrium alba (White Cockle) 

Petals usually white (sometimes pink). Sepals 15-30 mm long. Petal blade 8-12 mm long.

(5) Prunella vulgaris (Healall) 

This plant often has rhizomes. Stems square, 6 cm to .5 m tall. Leaves 2-9 cm long, .7-4 cm wide. Petals pink purple to pink or white, 12-18 mm long. Found in wet meadows, streamsides, and other moist sites. Widespread in temperate North America and in Eurasia.

(6) Saponaria officinalis (Bouncingbet) 

Perennial, 30-80 cm tall, forming clumps. Leaves are 3-12 cm long, .8-4 cm wide. Each leaf has three prominent veins extending from the base to the leaf tip. When cut, no milky juice exudes from veins. Many flowers, with white or pink petals. Widely established in North America; introduced from Europe. This plant is poisonous to livestock due to the presence of saponins, the soapy substances in the juice.

(7) Silene noctiflora (Nightflowering Catchfly) 

Annual plant, growing erect with only one stem, or the stem sometimes branching towards the top of the plant. Petals are yellowish beneath, pink above. Sepals are 12-25 mm long. There are 10 green veins extending up the sepals, with white between the veins.

(8) Silene vulgaris (Bladder Campion) 

Perennial plant. 20 veins extend up the sepals. The outer cup is papery and looks inflated.

(9) Stellaria media (Common Chickweed) 

Annual or biennial herb. The plant forms loose mats or clumps. Stems are 1-5 dm long, and can take root at the nodes. Petals white, 2-6 mm long. Weedy plants of open sites. Widely established in North America, adventive from Eurasia.

(10) Vaccaria pyramidata (Cow Cockle) 

Petals pink. Sepals 11-15 mm long. Petal blade 5-8 mm long.

(11) Verbena hastata (Vervain) 

Stems 4-15 dm tall. Leaves 5-15 cm long. The lower leaves can sometimes be variously shaped. Flowering portion consisting of numerous erect, narrow (to 7 mm wide) spikes. Petals are blue, purplish or pink, about 3 mm long. Found in wet meadows, marshes and bogs. Widely distributed in the U. S. and southern Canada.

Petals yellow

(1) Bidens (Beggartick) 

Annual plants with fibrous roots. Flowering time is spring or autumn. 5-12 Green bracts surround the flower head. The seed has 2-4 bristles protruding from the top. Each bristle has small barbs that point downward towards the seed. Various species are found in Eurasia, N. Africa, Australia, and N. America.

(2) Helianthus (Sunflower) 

Leaves are opposite on the lower stem, often alternate on the upper stem.

(3) Hypericum (St. Johnswort) 

Leaves, and often petals, are dotted with oil glands. Flower has five yellow petals. Each flower has about 3 bundles of stamens. Each bundle has many stamens (too many to count). The fruit is a capsule, between 5-10 mm long. Germination is in the spring. Flowering time is in the summer or in autumn. Can grow in nutrient-poor soil.

Lobed or divided

Petals blue, pink, or purple

(1) Erodium cicutarium (Storksbill) 

Winter annual or biennial. The base of the plant is a rosette of leaves. Stems from this rosette are from 1 inch to 2 feet long. Leaves are divided into tiny lobes, giving the leaf a feather-like appearance. Leaves and stems are hairy. Flowers are borne in clusters of 2 or more. The fruit is a long, pointed beak. Native to Europe or Asia, now common worldwide.

(2) Proboscidea (Devil's Claw/Unicornplant) 

Annuals. Plants grow spreading on the ground. Stems are 30-80 cm long. Leaves can vary somewhat in shape. Petals are yellow, copper colored, dull white or purplish, spotted with purple or yellow. Fruit is a large pod. The pod base is oval, between 6-10 cm long. A beak extends from this pod, which splits into two curved claws upon drying. They are equal to, or a little longer than, the oval base. Range: Delaware to Colorado and California, southward to Mexico. (From A Flora of New Mexico, Hutchins, p. 1856-1859)

(3) Verbena (Vervain) 

Annual or perennial herbs. Flowering portion made up of spikes of small blue or purple flowers. Petals are fused to form a funnel shape. Each spike has many small, green, leaf-like bracts between the flowers.

Petals white

(1) Ambrosia (Ragweed) 

Small, white flower heads are borne on elongate stalks. Flower heads are between 3-6 mm wide.

(2) Proboscidea (Devil's Claw/Unicornplant) 

Annuals. Plants grow spreading on the ground. Stems are 30-80 cm long. Leaves can vary somewhat in shape. Petals are yellow, copper colored, dull white or purplish, spotted with purple or yellow. Flowers are between 2.5-4 cm long. Fruit is a large pod. The pod base is oval, between 6-10 cm long. A beak extends from this pod, which splits into two curved claws upon drying. They are equal to, or a little longer than, the oval base. Range: Delaware to Colorado and California, southward to Mexico. (From A Flora of New Mexico, Hutchins, p. 1859.)

Petals yellow

(1) Bidens bipinnata (Beggartick) 

Annual plant with fibrous roots. 3-12 dm tall. Leaf stalks are 2-5 cm long. Flowering time is summer or autumn. 7-10 green bracts surround the flower head. Seeds are tetragonal, often black. There are 3-4 projections off the top of the seed. Found in most of the eastern U. S.; Mexico and much of South America; widespread in the Old World. (From Manual of the Vascular Plants of Texas, Correll and Johnston, p. 1663.)

(2) Proboscidea parviflora (Devil's Claw/Unicornplant) 

Annuals. Plants grow spreading on the ground. Stems are 30-80 cm long. Leaves can vary somewhat in shape. Petals are yellow, copper colored, dull white or purplish, spotted with purple or yellow. Flowers are between 2.5-4 cm long. Fruit is a large pod. The pod base is oval, between 6-10 cm long. A beak extends from this pod, which splits into two curved claws upon drying. They are equal to, or a little longer than, the oval base. Range: Delaware to Colorado and California, southward to Mexico. (From A Flora of New Mexico, Hutchins, p. 1856-1859.)

(3) Tribulus terrestris (Puncturevine) 

Annual herbs, spreading on the ground. Flowers are found in the angle between the leaf and the stem. Fruits have strongly spined nutlets. Spines can puncture tires and injure feet. Found in open sites. Widespread in the U. S.; native to the Old World.

Spade-shaped

Nepeta cataria (Catnip)

Stems square, 3-10 dm tall. Flowers are whitish, spotted with purple. Flower length is 7-12 mm long. Usually found in moist sites. Native to Europe, now widely distributed in North America.

WHORLED LEAVES WEED

Whroled Leaves Weed Crop Pests (1) Aizoaceae

  Mollugo verticillata (Carpetweed)

(2) Caryophyllaceae

  Spergula arvensis (Corn spurry)

(3) Rubiaceae

  Galium aparine (Catchweed bedstraw)

BASAL LEAVES/ROSETTE

Basal Leaves or Rosette Weed Crop Pests

(1) Apiaceae

  Hydrocotyle umbellata (Pennywort spp.)

(2) Asteraceae

  Hieracium aurantiacum (Hawkweed)

  Taraxacum officinale (Dandelion)

  Bellis perennis (English daisy)

(3) Euphorbiaceae

  Eremocarpus setigerus (Turkey mullein)

(4) Plantaginaceae

  Plantago lanceolata(Buckhorn Plantain)

  Plantago major(Broadleaf Plantain)

  Plantago rugelii(Plantain)

(5) Ranunculaceae

  Ranunculus testiculatus(Bur Buttercup)

TREES

Tree Crop Pests

(1) Aceraceae

  Acer(Maple)

(2) Betulaceae

  Betula(Birch)

(3) Fabaceae

  Robinia pseudoacacia(Black Locust)

(4) Salicaceae

  Salix(Willow)

(5) Ulmaceae

  Celtis(Hackberry)

SHRUBS

Shrub Crop Pests

(1) Anacardiaceae

  Rhus vernix (Poison sumac)

(2) Asteraceae

  Artemisia tridentata(Big Sagebrush)

  Gutierrezia    (Snakeweed spp.)

(3) Betulaceae

  Ostrya knowltonii (Western Hophornbeam)

(4) Caprifoliaceae

  Symphoricarpos (Snowberry spp.)

(5) Chenopodiaceae

  Atriplex confertifolia(Shadscale)

(6) Rosaceae

  Crataegus douglasii (River hawthorn)

  Prunus fasciculata (Desert almond)

  Rosa (Rose spp.)

  Rubus idaeus (Raspberry)

(7) Verbenaceae

  Lantana camara (Lantana)

VINES/TRAILING

Vines and Trailing Weed Crop Pests

(1) Asclepiadaceae

  Funastrum heterophyllum (Climbing milkweed)

(2) Bignoniaceae

  Campsis radicans (Trumpetcreeper)

(3) Convolvulaceae

  Morningglory Family

(4) Cucurbitaceae

  Momordica charantia (Balsam apple)

(5) Cuscutaceae

  Sicyos angulatus (Burcucumber)

  Cuscuta indecora (Largeseed dodder)

  Cuscuta campestris (Field dodder)

(6) Polygonaceae

  Fallopia Adans. (Synonym: Bilderdykia Dumort) Synonym for B. convolvulus (?)

AQUATIC

Aquatic Weed Crop Pests

(1) Alismaceae

  Sagittaria sagittifolia (Arrowhead)

(2) Ceratophyllaceae

  Ceratophyllum demersum (Coontail spp.)

(3) Nymphaeaceae

  Nymphaea (White waterlily)

(4) Typhaceae

  Typha latifolia (Cattail)