Astragalus mollissimus.—This, the woolly loco weed, is perhaps the best known of all the loco weeds. It is the species most abundant in Colorado, where from 1881 to 1885 nearly $200,000 was paid out in bounties in an attempt to exterminate it. The plant is still abundant in that State, and reports of the damage done by it continue frequent. Specimens of the three following species of Astragalus have been forwarded to the Division of Botany with the information that they were causing great financial loss in the districts noted. It is quite probable that other species are dangerous also.
Fig. 88.—White loco weed (Aragallus spicatus) in flower.
(From the Annual Report, U.S.A. Department of Agriculture, 1900.)
Fig. 89.—White loco weed (Aragallus spicatus), showing seed pods.
(From the Annual Report, U.S.A. Department of Agriculture, 1900.)
Fig. 90.—Loco weed (Astragalus splendens).
(From the Annual Report, U.S.A. Department of Agriculture, 1900.)
POISONING BY WHITE LOCO WEED (ARAGALLUS SPICATUS).
Fig. 91.—Stemless loco weed (Aragallus lambertii). a, Flowering plant; b, seed pods; c, cross-section of seed pod—all one-third natural size.