STOCK-POISOXIXG PLANTS OF THE RANGE 



17 



spurs, owing to the fact that it occurs in such enormous masses. 

 There are regions in Colorado and Utah where many acres are almost 

 carpeted with these plants. They occur early in the spring, imme- 

 diately after the snow disappears, growing more rapidly than the 

 grasses, so that in ^ome regions they seem for the time almost to 

 preempt the soil. These low larkspurs blossom comparatively early 

 in the season, and in Colorado D. menziesii dries up and disappears 

 not far from the first of July. Consequently the cases of poisoning 

 from low lark-purs occur almost entirely in May and June. 



It will be noted that the leaves of the low larkspurs are quite 

 different from those of the tall larkspurs, but are easily recognized 

 after one becomes fairly familiar with them. 



Figure 9. — A group of plants of the tall larkspur. Delphinium barbeyi, growing in 

 natural surroundings. The white background brings out the plants more clearly. 

 This species is the most widely distributed of the tall larkspurs and is responsible 

 for greater losses of cattle than any other species. It extends from Colorado to 

 the Sierras 



There is another low larkspur. Delphinium bicolor, occurring com- 

 monly in Montana, which is typical of somewhat lower altitudes 

 than D. menziesii and apparently never grows in sufficiently large 

 masses to be dangerous. One of the low larkspurs, the Anderson 

 larkspur. I), andersomi, growing in Nevada, California, and Oregon, 

 causes many fatalities. 



The low larkspurs are poisonous throughout the whole period of 

 their lives, while the tall larkspurs gradually lose their poisonous 

 properties after blossoming. 



In Plate 11 is shown the Plains larkspur. D. vireseens, which has 

 white blossoms. This is common in the Plains region east of the 

 Rocky Mountains; it probably occurs rarely in sufficient abundance 

 to cause harm, but there is reason to think that in some seasons it has 

 occasioned the death of a considerable number of cattle. 



452S2 3 — 29 — —2 



