I46 PEA FAMILY 



tipped. Pod 1 in. or less long, ovate, incurved, thick-walled, 

 densely long-hairy, sessile in the calyx. — Eastern ranges of 

 the Sierra Nevada and therefore to be expected along our 

 borders. A compact, gray plant, instantly recognized by its 

 woolly pods. 



3. A. whitneyi Gray. Leaflets 11 to 19, linear, J4 to V* in- 

 long. Flowers violet. Pod 1 to 1^2 in. long, balloon-like, with 

 thin walls, glabrous, narrowed at base to a stalk longer than 

 the calyx. — Mt. Warren and other high peaks near the des- 

 ert; doubtless occurs along our eastern borders. 



4. A. bolanderi Gray. Leaflets 17 to 27, linear-oblong, 

 entire, ^ to 1 in. long. Flowers nearly white. Pod 1 in. or 

 less long, slightly inflated, thick-walled, incurved, on a stalk 

 longer than the calyx. 



This plant resembles no. 1 but may be distinguished by the 

 narrow leaflets and stalked pods. It varies from green to sil- 

 very pubescent. "Yosemite Valley" is given as the type 

 locality, but we did not find it there, although it grows near 

 Eagle Peak, Snow Flat, Peregoy Meadows, and elsewhere in 

 open, gravelly places. 



The name "Loco-weed" has been applied to this genus of 

 plants because of their tendency to produce symptoms of 

 insanity in animals when eaten, loco being the Spanish for 

 "crack-brained." While most animals will not touch the 

 weeds, some of them, especially young or underfed ones, will 

 occasionally nibble the herbage, then eat more freely, and 

 finally acquire the "loco habit," which is likely to be trans- 

 mitted to other members of the flock or herd. It has recently 

 been discovered that the poisonous effect is not due to the 

 weed itself but to the metal barium, which the plant takes up 

 from the soil. Since the amount taken up and the form in 

 which it occurs varies with local conditions, a species may be 

 poisonous in one locality and harmless in another, hence the 

 wide difference of opinion among stockmen as to the danger 

 from loco-weeds. 



5. A. kentrophyta Gray. Leaflets 5 to 7, narrow, rigid and 

 spine-like, not J/£ in. long. Flowers only 1 to 5 on each 

 peduncle, whitish. Pod ovate, pointed, J4 m - l° n g> sessile in 

 the calyx. — A matted plant, 6 in. or less high, found near the 

 summits of Mt. Warren and Mt. Dana and also in the 

 Rocky Mts. 



A. congdonii Wats, comes from Hites Cove, below the 

 Yosemite Valley and may be known by its linear reflexed 

 pods. 



