470 
(2) Plants with a glaucous foliage having a hard epidermis: 
Agropyron repens glaucum, 
Elymus canadensis glaucifolius. 
Yucea glauca. 
Zygadenus venenosus. 
Rumex venosus. 
Adorium tenuifotium, 
Argemone alba. 
Viola nuttallii. 
(3) Plants with white, often shreddy, stems: 
Gnothera pallida. 
(nothera albicaulis. 
Mentzelia nuda. 
Mentzelia oligosperma. 
Mentzelia decapetala. 
(4) Plants in which the surface is reduced to a minimum, either by a 
special habit, as in the species of Opuntia and Cactus, or by the leaves 
being narrow and involute, as in the following: 
Calamovilfa longifolia. 
Lygodesmia juncea, 
Carex filifolia. 
Carex stenophylla. 
(5) Plants with a deep-seated, enlarged root: 
Tpomwa leptophytla.' Psoralea esculenta, 
Many of the plants belonging to the Dry-plain flora, and supposed to 
be of more southern or western range, extend into the foothills. Among 
these may be mentioned: 
Jacksonia trachysperma. 
Astragalus plattensis, 
Astragalus racemosus. 
Astragalus spatulatus, 
Astragalus gracilis. 
Psoralea cuspidata. 
Adorium tenuifolium. 
Peucedanum villosum. 
Erigeron canus, 
Hrigeron flagellaris. 
Croton tecensis, 
Sedum stenopetalum. 
Astragalus microlobus. 
Chenopodium fremonti incanum. 
In many places in western Nebraska and South Dakota and eastern 
Wyoming there are no visible streams. The superfluous water is 
drained off by means of “sand draws.” A sand draw is a subterranean 
stream, On the surface is seen only a broader or narrower band of 
pure sand, marking the channel. The water may sometimes be run- 
ning 5 meters below the surface. Sand draws are found here or there 
among the foothills, but their place is mainly taken by the numerous 
streams running down from the hills. Many of these streams sink, 
however, and become sand draws before they reach Cheyenne River. 
Many plants either from the Black Hills proper or from the Missouri 
Valley have spread along the water courses. 
ascended the streams may be mentioned :? 
Among those which have 
Ranunculus macounti. Pentstemon grandiflorus, 
Prunella vulgaris, 
Polygonum lapathifolium. 
Roripa nasturtium, 
Cenothera sinuata, 
‘At the State University of Nebraska there is a root preserved which, in its dry 
state, is three-fourths of a meter long and 3.5 decimeters in diameter. 
? Plants ranging across the continent or found as well in the Mississippi Valley as 
in the Rocky Mountains are mostly omitted. 
