Woolly loco

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Woolly loco flowers and calyces

Woolly loco

Woolly loco

Woolly loco pods

Woolly loco

Morphology

Stem

1 to several, stout, .5 to 5.5 inches long, densely soft hairy; outer stems prostrate, inner stems ascending.

Leaves

Alternate, ascending or arching, 3 to 10 inches long, .5 to 1.5 inch wide, odd-pinnately compound; leaflets 15-33, oval, .25 to 1 inch long, densely fuzzy pubescent.

Inflorescence

Racemes, on stalks 2 to 8 inches long, oblong, 2 to 4 inches long, 10-40-flowered.

Flower

Calyces 5-lobed; corollas papilionaceous, reddish purple to yellowish purple, fading bluish; banner prominent, .75 to 1 inch long; stamens 10, 9 united, 1 free.

Fruit

Pods, crescent-shaped, 2-celled, .5 to 1 inch long, short-beaked, usually glabrous; seeds smooth, brown.

Ecology

Habitat

Prairies, pastures, hillsides, stream valleys, and roadsides, most abundant in rocky or sandy soils.

Distribution

West half of Kansas.

Practical Information

Toxicity

This native legume is highly poisonous to livestock. It is unpalatable, but once a small amount is consumed, the animal will seek it to the exclusion of other plants. Horses are particularly susceptible. The toxic effects are cumulative. Symptoms of woolly loco poisoning are: slow staggering gait, loss of weight, rough hair coat, disorientation, depression, and anxiety. The optic nerves are affected, causing horses to shy violently, to be difficult to back up, and to bump into obstructions - i.e. to exhibit "loco" behavior. Pastures with woolly loco should not be grazed until the plants have matured and withered away.