Dalmatian Toadflax
Linaria dalmatica (L.) Mill.

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

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 1/2 in. 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.

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, alternative, basal leaves whorled, upper leaves much reduced. Covered with fine hair.

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

Flower: 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 reduceproductive potential of infested rangelands.

Leafy Spurge
Euphorbia esula L.

Growth Habit: Perennial, erect, up to 3 ft. tall, spreading by seed or creeping roots.

Leaves: Alternate, long, narrow, 1/4 in. wide and 2 in. long, usually drooping.

Stems: Branched near top, hairless, entire plant contains milky sap.

Flowers: Inconspicuous, surrounded by large heart shaped floral leaves which turn yellow-green near maturity.

Roots: Brown, numerouse pink buds, deep, streading, very persistent.

Other: Grows in nearly all soil types and habitats. Seed is thrown to 20 ft. by exploding seed capsule.

Meadow Knapweed
Centaurea pratensis

Growth Habit: Perennial, erect to 3 1/2 ft. tall.

Leaves: Lower leaves - long stalked, smooth margins, coarsely lobed or toothed. Middle leaves - without stalks, smooth or toothed margins. Upper leaves - much reduced and smooth margins.

Stems: Stiff, many branched, covered with fine hair.

Flower: Large pink to purplish-red heads ar the ends of branches. Bracts deeply fringed, light to dark brown.

Roots: Taproot.

Seeds: 1/8 in. long tipped with a tuft of bristles.

Other: Roadsides, waste areas, fields, and pastures.

Orange Hawkweed
Hieracium aurantiacum L.

Growth Habit: Perennial, erect to 12 in. tall.

Leaves: Lance-shaped, hairy, leaves are basal, occasionally 1 to 2 small leaves on stem.

Stems: Erect, bristly, terminate, in an umbel of flower heads.

Flowers: 5 to 30 per plant, red-orange, petals with notched tips.

Roots: Fibrous.

Other: Entire plant contains a milky juice.

Perennial Pepperweed
Lepidium latifolium L.

Growth Habit: Erect perennial, numerous stems, spreading by seed and deep-seated rootstocks.

Leaves: Alternate, lance shaped, bright green to gray-green waxy, smooth to toothed margins, basal leaves larger than upper leaves.

Stems: Branched, smooth, waxy, 1-3 feet tall.

Flowers: Raceme of small white flowers in dense clusters near branch ends.

Roots: Deep-seated and spreading.

Seeds: Small, rounded, flattened, slightly hairy, 1/16 in. long, reddish brown.

Other: Deep roots make it difficult to control.

Plumeless Thistle
Carduus acanthoides L.

Growth Habit: Biennial, sometimes annual, erect, up to 8 ft. tall. Rosette formed first year, flowering stem elongates second year.

Leaves: Dark green with a light midrib, hair only on the underside, leaf margin with sharp spines.

Stems: To 4 ft. tall, erect, winged to flowering heads.

Flowers: Solitary, terminal or clusters of 2 to 5. Narrow seedhead bracts spine tipped. Reddish-purple blooms 1/2 to 1 in. diameter.

Roots: Stout, fleshy taproot.

Seeds: Striped lengthwise, slightly curved, with a protrusion at one end.

Other: Reproduce by seed only.

Puncturevine
Tribulus terrestris L.

Growth Habit: Annual, mat forming, trailing stems to 5 feet long.

Leaves: Oppposite, hairy, divided into 4 to 8 pairs of leaflets. Oval leaflets 1/4 to 1/2 in. long.

Stems: Prostrate, trailing, hairy, many branched from root crown.

Flower: 5 petals, yellow, in leaf axils, to 1/2 in. wide.

Roots: Fibrous.

Seeds: Fruit break into 5 sections with 2 to 4 seeds per capsule. Capsule tack like structures with 2 sharp spines, resembling the head of a goat.

Purple Loosestrife
Lythrum salicaria L.

Growth Habit: Perennial, erect to 8 feet tall, associated with moist or marshy areas.

Leaves: Simple, lance-shaped, smooth margins, opposite or whorled.

Stems: branched, terminating in flowering stalks.

Flower: Rose-purple flowers having 5 to 7 petals and numerous stamens, in long, vertical recemes.

Roots: Large, fleshy, adapted to aquatic sites.

Other: Dense infestations can impede water flow in canals and ditches.

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 - intermediate in size, slight toothed margins; Basal leaves - deeply notched.

Stems: Numerouse branches, each ending with a single flower.

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

Roots: Dark brown to black and heavily scaled.

Seeds: Flattened, ivory colored, retained in cupshaped seed heads.

Other: Leaves and stems covered with short stiff hairs giving plant an apperance of knap. Spreads by seeds and creeping rootstocks.

Scotch Thistle
Onopordum acanthium L.

Growth Habit: Biennial, sometimes annual, erect, up to 8 ft. tall. Rosette formed first year, flowering stem elongates second year.

Leaves: Large, coursely lobed, hairy on both sides, velvety gray appearance. Margins lined with sharp conspicuous spines. Basal leaves up to 2 ft. long and 1 ft. wide.

Stems: Erect, branching, spiny leaf wings extend down onto stem, covered with dense fine hairs.

Flower: Solitary, terminal, 1 to 2 inches in diameter, violet to reddish colored. Bracts spine tipped.

Roots: Large fleshy taproot.

Seeds: Deep brown to black, distinctly wrinkled, 3/16 in. long.

Other: Reproduce by seed only. Dense strands may be impenetrable to recreationists, livestock, or wildlife.

Sulfur Cinquefoil
Potentilla recta L.

Growth Habit: Erect, long-lived perennial, reproducting by seed, plant my form a ring of plants as the older center dies out and new stems grow on the outside edges.

Leaves: Palmate compound, 7 leaflets, coarse stiff hair on upper and lower surfaces, yellowish green.

Stems: One of several, 12 to 28 in. tall, branched near top, covered with hairs. Numerouse leaves along stem, few from base.

Flower: 1/2 to 1 inch in diameter, pale yellow, large yellowish green buds. May bloom late May throughout summer.

Roots: Woody (No rhizomes).

Seeds: Very tiny 1/20 inch in diameter, rough.

Other: Forms dense monocultures, reduces grass production.

Tansy Ragwort
Senecio jacobaea L.

Growth Habit: Biennial or short-lived perennial, erect, branched near top. Reproduces by seed only.

Leaves: Alternate, deeply lobed with irregular margins, terminal lobe larger than lateral ones, cobwebby hairs in early growth stages.

Stems: Simple, usually single, to 6 ft. tall.

Flower: Flower heads yellow, numerous, in clusters, about 1 inch in diameter.

Roots: Small to medium taproot.

Seeds: Small, striped, with a protrusion at one end.

Other: Toxic to cattle and horse producing irreversible liver damage.

Yellow Hawkweed
Hieracium pratense Tausch.

Growth Habit: Perennial, erect to 12 in. tall.

Leaves: Lance-shaped, hairy, leaves are basal, occasionally 1 to 2 small leaves on stem.

Stems: Erect, bristly, terminated in an umbel of flower.

Flower: 5 to 30 per plant, yellow petals.

Roots: Fibrous.

Other: Entire plant contains a milky juice.

Yellow Starthistle
Centaurea solstitialis L.

Growth Habit: Annual, erect, rigid branching stems.

Leaves: Basal leaves deeply lobed, upper leaves not lobed, small, sharply pointed.

Stems: Rigid, covered with a cottony fiber, to 30 in. tall, winged structures.

Flowers: Yellow, terminal, flower bracts are tipped with straw-colored, 3/4 in. thorn.

Roots: Taproot.

Seeds: Smooth, light-colored, often darker mottled, 1/8 in. long, notched just above the base.

Other: Causes "chewing disease" in horses.

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 ft. 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 in. long pineapple-shaped or vase-shaped seed capsules.

Other: All parts of this plant are toxic.

Bull Thistle
Cirsium vulgare (Savi) Tenore

Growth Habit: Biennial, erect, many spreading branches. Rosette formed first year, flowering stem elongates second year.

Leaves: Green, sparsely hairy, with short appressed prickles on the surface, cottony below. Sharp spines on the margins.

Stems: Stout, 2 ft. to 5 ft. tall with spiny wings from leaves.

Flowers: Terminal, more or less clustered, 1 1/2 to 2 in. wide, flowers dark purple, bracts spine tipped.

Roots: Short fleshy taproot.

Seeds: Straw colored, striped lengthwise with brown or black, a protrusion at one end.

Other: Reproduce by seed only.

St. Johnswort
Hypericum perforatum L.

Growth Habit: Perennial, erect, numerous branches.

Leaves: Opposite, attached directly to stem, 1 in. long, oblong, covered with transparent dots.

Stems: Woody at the base, 1 to 3 ft. tall, rust colored, with 2 ridges.

Flowers: Yellow, 3/4 in. diameter, numerous in flat-topped clusters, 5 petals with numerous stamens.

Roots: Branched and deep, some shallow and capable of sending up shoots.

Seeds: Small, shiny black, with rough texture in a round, pointed, three-part seedpod.

Other: Contains a toxic substance which causes white-haired animals to become allergic to strong sunlight.

Canada Thistle
Cirsium arvense L.

Growth Habit: Perennial, erect, up to 4 ft. tall.

Leaves: Varies from light to dark green, oblong or lance shaped, deeply cut, spiny toothed margins (some may be smooth); slightly hairy below. Tremendous leaf variability.

Stems: Smooth to slightly hairy, branched at top.

Flower: Small bristly clusters, 3/8 to 5/8 inch in diameter, light lavender to deep rose purple. Plants are male or female.

Roots: Extensive, fleshly, creeping rootstocks.

Seeds: Smooth, light to dark brown, tipped by a cupped conical point, approx. 1/8 in. long.

Other: Reproduces by seed and creeping rootstocks.

Poison Hemlock
Conium maculatum L.

Growth Habit: Biennial, erect to 10 ft. tall.

Leaves: Shiny green, fern-like, finely divided 3 to 4 times. Lower leaves have long stalks clasping the stem. Upper leaves on short stalks. Musty odor.

Stems: Stout, branched, purple-spotted with distinct ridges.

Flowers: Numerous umbrella shaped clusters of tiny white flowers without sepals. Clusters suppoted by stalks whorled at branch terminals.

Roots: Large white taproot.

Seeds: Paired, 1/8 in. long, ribbed, concave, light brown.

Other: All parts are poisonous.

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 sometimes branched.

Flower: Snapdragon type, 1 to 1 1/2 in. long with spur, bright yellow with deep orange center.

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

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

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