related 0. saximontana (syn. O. albiflora (A. Nels.) K. Schum., not Bunge), 

 for which the term white loco is more appropriate, and which are discussed 

 under W138. More field and laboratory study of these pla.nts is needed, but it 

 seems probable that, even though albino forms of O. lambertii occur, they are 

 relatively rare. Furthermore, it seems likely that the typically white-flowered 

 0. macounii (of which O. saximontana may perhaps prove to be a variety or 

 form) is, to a considerable extent, the. O. lambertii of range literature, and 

 that it differs from O. lambertii not only in color of flowers, but also in char- 

 acters of calyx, pod, and density of inflorescence. 



Crazyweed is also called stemless loco and, less frequently, rattleweed. 

 However, it seems preferable to restrict loco to the genus Astragalus. In one 

 of the oldest State lists of poisonous plants published in this country, 2 Oxytropis 

 lambertii is called crazy weed, and that name is adopted here. Pursh * named 

 this species lambertii after the wealthy English botanist, Aylmer Bourke Lam- 

 bert. He credits (John) Bradbury with having first collected the species along 

 the Missouri River. Aven Nelson, 3 after a study of Bradbury's travels, estimates 

 the type locality as "not far from Yankton", S. Dak. 



Owing to the confusion in the manuals and in poisonous-plant literature 

 about union of the typically white-flowered forms with the typically purple- 

 flowered 0. lambertU, the range of crazyweed cannot be given with precision. 

 It is, without doubt, one of the most common and widely distributed American 

 species of Oxytropis, yet probably too wide a range has been ascribed to it. On 

 a conservative basis, the species may be considered to occur from Minnesota 

 to Montana, and southward to Texas and Arizona. It has a wide altitudinal 

 distribution, growing on plains and hillsides up to the aspen and Engelmann 

 spruce-lodgepole pine belts of the high mountains, attaining an elevation of 

 about 10,000 feet in Colorado and the Southwest. It is usually more abundant 

 and characteristic of the higher elevations than the white-flowered species 

 mentioned. Crazyweed seldom appears in pure stands ; however, it frequently 

 forms numerous patches over extensive local areas, and often increases rapidly 

 on overgrazed ranges. The deep, thickened, woody taproot enables it to with- 

 stand both trampling and drought. This poisonous weed prefers open, well- 

 drained, sandy, or gravelly soils. 



Normally, crazyweed is unpalatable to livestock; cattle, horses, and sheep, 

 however, eat it freely when palatable forage is scarce or absent. 



Admittedly, crazyweed causes losses of livestock from locoism, but further 

 study is needed to determine the exact extent of the damage since, in most 

 of the loco-poisoning literature, the white-flowered forms are the ones empha- 

 sized. Chesnut and Wilcox * attribute the majority of the loco losses of 

 livestock in Montana to "white loco weed" (O. macounii, syn. Aragallus spicata) 

 and, although four other species of the genus are named as causing locoism 

 in that State, they do not include O. lambertii. Beath and co-workers 5 affirm 

 that "White loco (Oxytropis saximontana) is the plant commonly known in 

 Wyoming as the loco." It is significant that Marsh 67 consistently prefers the 

 common name of white loco for O. lambertii. Loco symptoms are similar, 

 regardless of the responsible species. 



Attempts to isolate and to determine the chemical identity of the poisonous 

 principle in crazyweed have thus far failed. 8 



1 Pursh, F. FLORAE AMEU1CAE SEPTENTRIONALIS ... 2 V., lllUS. London. 1814. 



2 Bessey, C. E. A PRELIMINARY ACCOUNT OF THE PLANTS OF NEBRASKA WHICH ARE 

 HEPUTED TO BE POISONOUS, OR SUSPECTED OF BEING so. Nebr. State Bd. Agr. Ann. Kept. 

 (1901) 16: 95-129, illus. 1902. 



3 Nelson, A. TAXONOMIC STUDIES, i. THE LOCO PLANTS. Wyo. Univ. Pubs.. Bot. 

 1 : [1091-121. 1926. 



* Chesnut V. K., and Wilcox, E. V. THE STOCK-POISONING PLANTS OF MONTANA : A 

 PRELIMINARY REPORT. U. S. Dept. Agr.. Div. Bot. Bull. 26, 150 pp., illus. 1901. 



6 Beath O. A., Draize, J. H., and Gilbert, C. S. PLANTS POISONOUS TO LIVESTOCK. 

 Wyo. Agr. Expt. Sta. Bull. 200, 84 pp., illus. 1934. 



8 Marsh, C. D. THE LOCO-WEED DISEASE. U. S. Dept. Agr. Farmers' Bull. 1054, 19 pp., 



' Marsh, C. D. STOCK-POISONING PLANTS OF THE RANGE. U. S. Dept. Agr. Bull. 1245. 

 rev., 75 pp., illus. 1929. Supersedes Bull. 575. 



8 Couch J F. A CONTRIBUTION TO THE STUDY OF LOCOISM. Jour. Pharmacol. and Expt. 

 Ther. 36 (1) : 55-83, illus. 1929. 



