Rocky Mountains. 461 



new species of prickly poppy,* with a spreading white flow- 

 er, as large as that of the common poppy of the gardens. 

 The aspect of this plant is very similar to that of the com- 

 mon poppy, except that the leaves are covered with innu- 

 merable large and strong prickles. When wounded it exudes 

 a thick yellowish sap, intensely bitter to the taste. On the 

 summits of some of the dry sandy ridges, we saw a few of 

 the plants called Adam's needles, (Yucca, angustifolid) 

 thriving with an appearance of luxuriance and verdure, in a 

 soil which bids defiance to almost every other species of ve- 

 getation. Nature has, however, fitted the yucca, for the un- 

 genial soil it is destined to occupy. The plant consists of a 

 large tuft of rigid spear-pointed leaves, placed immediately 

 upon the root, and sending up in the flowering season, a stalk 

 bearing a cluster of lilliaceous flowers as large as those of 

 the common tulip of the gardens. The root bears more re- 

 semblance to the trunk of a tree, than to the roots of ordi- 

 nary plants. It is two or three inches in diameter, descend- 

 ing undivided to a great depth below the surface, where it 

 is impossible the moisture of the earth should ever be ex- 

 hausted, and there terminates in numerous spreading branch- 

 es. In some instances the sand is blown from about the root, 

 leaving several feet of it exposed, and supporting the dense 

 leafy head, at some distance from the surface. f 



Several bisons and other game, had been seen in the course 

 of the day, but nothing taken. As our provisions were now 

 exhausted, it was resolved to remain encamped where we 

 were, while parties were sent out in different directions to 

 hunt4 



* Argemone alba, a large plant very distinct from A. mcxicana. 



f Other plants found here, were the great sunflower Helianthus gi- 

 ganteus, Asclepias obtusifolia, Ph., A. viridiflora, Ph., A. syriaca, and A. 

 incarnata, Amorpha canescens, N., Erigeron pumilum, N., A. Veronica 

 approaching V. beccabunga, Scutellaria galericulata, Rumex venosus, N., 

 and several which are believed to be undescribed. 



J In rain water puddles, we remarked a new species of Branchiopode 

 belonging to the genus Apus; small crustaceous animals, which exhibit 



