Sunlight/Crandall Weed Management Area

Weed Identification Efforts

Nine 8.5 in. x 11 in. laminated, color posters were produced for the Weed Tour and Weed Workshop. Some of the posters were located at the stops made during the tour. The other posters were available at the Wyoming Game & Fish Sunlight Habitat Unit. Weed identification booklets were also given to the participants. Our goal was to have each of the participants be especially aware of these noxious weeds.

 

Common tansy Tanacetum vulgare L.

Growth Habit: Perennial and aromatic.

Leaves: Alternate, deeply divided into numerous narrow, toothed segments.

Stem: 1.5 - 6 feet tall and often purplish-red in color.

Flowers: Yellow flower heads, 1/4 to 1/2 inch across, are numerous in flat-topped dense clusters.

Seeds: Yellowish-brown with short 5-toothed crowns.

Other: It is undesirable as forage for livestock and is sometimes mistaken for tansy ragwort.

Produced by: Weeds of the West, Western Society of Weed Science

 

Oxeye daisy Chrysanthemum leucanthemum L.

Growth Habit: An erect rhizomatous perennial, 10 to 24 inches tall, glabrous to sparsely hairy.

Leaves: Leaves progressively reduce in size upward on stem. Basal and lower stem leaves are oblanceolate to narrowly obovate, 2 to 5 in. long including the petiole, margin crenate to lobed or parted. Upper leaves become sessile and merely toothed.

Flowers: Flowering heads are solitary at the ends of branches, about 1.5 inches long. White ray flowers with-yellow disk flowers. Fruits have about 10 ribs.

Other: Flowering occurs from June through August.

Produced by: Weeds of the West, Western Society of Weed Science

 

Houndstongue Cynoglossum officinale L.

Growth Habit: Biennial, spread by seed. Rosette is formed on ground 1st year, flowering stalk elongates 2nd year.

Leaves: Velvety to touch. Basal-broad, lance-shaped. Upper- narrower, pointed, clasping stem.

Stems: Heavy, erect, usually branched above, to 3 ft. tall. Flowers: Dark red, rarely white, 1/4 inch in diameter in terminal clusters.

Roots: Taproot.

Seeds: Fruits consist of 4 flattened bur-like nutlets, each 1/4 inch long with short barbed appendages.

Other: Burs attach to hair and they have consumed a lethal amount. fur of animals and are easily transported. The plant is TOXIC to livestock, especially horses. Animals may survive for six months or longer after they have consumed a lethal amount.

Produced by: Wyoming Weed and Pest Council

 

Dalmatian toadflax Linaria dalmatica (L.) Mill.

Growth Habit: Perennial, often over 3 ft. tall.

Leaves: Light green, alternate, broad, heart-shaped, clasping the stem. Stem: Branching, light green, smooth and leafy.

Flowers: Snapdragon type, bright yellow, tinged with orange, to 1.5" long spur, born in upper leaf axils.

Roots: Vigorous, deep and extensive, creeping roots.

Seeds: Numerous, irregularly angled.

Other: Spread by seed and creeping roots.

Produced by: Wyoming Weed and Pest Council

 

Russian knapweed Centaurea repens L.

Growth Habit: Perennial herb, up to 3 ft. tall, erect, may be in dense clumps. Greyish color.

Leaves: alternate, simple, of several types: Upper leaves-small, narrow, unbroken edge; Stem leaves-intermediate in size, slight toothed margins; Basal leaves- deeply notched.

Stem: Numerous branched, each ending with a single flower.

Flower Head: Single, terminal, lavender, thistle like, scaly seed head.

Roots: Dark brown to black and heavily scaled.

Seeds: Flattened, ivory colored, retained in cup-shaped seed heads. giving plant an appearance of knap.

Other: Leaves and stems Spreads by seeds and creeping covered with short stiff hairs rootstocks.

Produced by: Wyoming Weed and Pest Council

 

Yellow toadflax Linaria vulgaris L.

Growth Habit: Perennial, often over 3 ft. tall. Leaves: Long and narrow, numerous, pale green, smooth and pointed, attached directly to the stem.

Stem: Smooth, erect and some times branched.

Flower: Snapdragon type, 1 to 1.5 inches long with spur, bright yellow with deep orange center.

Roots: Woody, vigourous, well branched with many laterals.

Seeds: Round, 1/2" in diameter, dark brown to black with papery circular wing.

Other: Spreads by seeds and creeping roots. Also called "Butter-and eggs."

Produced by: Wyoming Weed and Pest Council

 

Diffuse knapweed Centaurea diffusa Lam.

Growth Habit: Annual or biennial, bushy, up to 2 ft. tall. Rosette formed first year, flowering stalk elongates second year.

Leaves: Greyish-green, alternate, basal leaves whorled, upper leaves much reduced. Covered with fine hair.

Stem: Hairy, erect, single main stem from a rootstock, branched near or above the base.

Flowers: Solitary, usually white, sometimes pink, rose, or lavender; seedhead bracts end as sharp, rigid spines.

Roots: Elongated taproot.

Seeds: Oblong, dark brown or grey with longitudinal lines.

Other: May seriously reduce productive potential of infested rangelands

Produced by: Wyoming Weed and Pest Council

 

Spotted knapweed Centaurea repens L.

Growth Habit: Biennial or short lived perennial, up to 3 ft. tall. Rosette formed first year, flowering stalk elongates second year.

Leaves: Long and divided below, short and narrow above. Covered with fine hair.

Stem: Erect and slender wiry branches. Covered with fine hair.

Flower: Seed heads mostly on branch tips, solitary, to 1" diameter. Pink to purple, rarely white. Seed head bracts are black tipped, with 5-7 pairs of short feathery appendages.

Roots: Taproot not well developed. Seeds: Brownish, 1/8" long,

Other: Very agressive, can infest-notched on one side of base, large areas quickly, offers very little short tuft of bristles at tip end. big game or livestock forage value.

Produced by: Wyoming Weed and Pest Council

 

Black henbane Hyoscyamus niger L.

Growth Habit: Erect, bushy, annual or biennial. Reproduces by seed only.

Leaves: Alternate, coarsely toothed, shallowly lobed, very hairy. Foliage has a foul odor.

Stems: Erect, branched, 1-3 feet tall. Flowers: Large, 1-2 inches in diameter, brownish-yellow with a purple center and purple veins. Flowers from upper leaf axils.

Roots: Medium taproot.

Seeds: Tiny, black; hundreds in 1 inch long pineapple-shaped or vase-shaped seed capsules.

Other: All parts of this plant are TOXIC.

Produced by: Wyoming Weed and Pest Council