BOTANICAL INFORMATION. 459 
Chrysopsis villosa. The more fertile parts of the valley still 
present Pentstemon grandiflorum, and Batschia Gmelini, with 
Lathyrus palustris, Sisyrinchium anceps, Pentst. pubescens, 
Potentilla anserina, Zigadenus, Aster, and Solidago, in moist 
places. 
"The sand hills are held together by the long binding roots 
of Psoralea arenaria and Rumex venosus; in part, also, by 
Glycyrrhiza lepidota and Cerasus pumila, which latter seems 
to me a true plum, as regards the fruit; sometimes it grows 
only a span high, with a dozen fruits of the size of a sloe. 
Out of these thickly clustered masses springs the robust 
Carduus argyrophyllus, Torr.? with its large, white, and ` 
. very fragrant heads of flowers. Most showy are the thyrses 
of the Rumez venosus, of which the large winged fruits become 
scarlet towards maturity. The singular and transient flora 
of these sandhills disappears in less than four weeks, when 
everything dries up, and no vegetable life remains, except 
masses of Orobanche, growing out of the roots of roses and 
the Psoralea or Giycyrrhiza. 
But it is to the gravelly plains and ridges that the attention 
of the botanist is chiefly attracted ; especially the wide ex- 
tending ridges, which, wherever they appear, give shelter to 
the rarest and choicest plants of the surrounding country. 
These ridges prevail along the whole eastern slope of the 
Rocky Mountains; alternating with almost every geological 
formation ; and may be traced across the Missouri, about the 
mouth of Platte river eastward, in an irregular interrupted 
line to Lake Michigan, and southward likewise to the Ozark 
Mountains of Missouri; perhaps, also theod Arkansas to 
Texas. 
The plants of these ridges bear a resemblance to the Sub- 
alpine Flora, with somewhat of the robustness of those species 
which inhabit the plains below. There are no grasses with 
creeping roots, except the simple Panicum Muhlenbergii, in | 
this region, and on the upper Missouri ; but several beautiful 
Graminee grow only here, amongst which are Aristida pallens . 
and Agrostis brevifolia. a Ki decreas and Ses- 
