227 



tcrinediate forms can be traced. Ckri/sitpsis rillosa Nutfc. and Aplo- 

 2mppns ,spintdo,sus DO. are well known to be qnite variable, bnt their 

 variations, to tlie eastward and Avestward especially, will nearly always 

 be found to be in the line of a greater or less presence of i>rotective 

 characters. Of the former, the very names of many of the described 

 varieties on^ht to, and do, indicate thes<^ facts, such as oaneseenn, hispida, 

 foUosa, nteno2)h}/lla, viseidayetc., while tliere ar«^ innumerable interme- 

 diate forms not worthy of varietal rank, Riddfllia tdffi'fina Xntt. be- 

 comes mucli more woolly farther westwai-<l. and Kiufelmannut pinmitifida 

 T(n'r. and (J ray moie hairy and somewliat dwai'fed. 



Besides (■liri/sopsiH villo.sa Nutt, a- number of otlier species become 

 so modilicd as to })rodnc<' distinct varieties. Piialosteinon violttcens 

 Mx. changes into its dwarfed but stouter variety tt'nid.s CouUer. Oxy- 

 IxiphuH nt/utaginens Sweet, becominj;' more and more hairy, finally pro- 

 duces the variety pilosus (Iray (Barber County, Kans.), (h'nothcra 

 Jldrtivegi Bentli. beconu;s tlie vari(ity larendit.ln'Jolia Wats,, dwarfed 

 and more hairy, and A.stcr oblongifolhis ^utt, <iives |>]ace to its dwarfed 

 but stouter and more rij>i(l variety rigiduln.s (Iray, 



Just so, species with thickened or hairy epidermis and tl(,'shy, narrow 

 leaves take the place of otlier species of the same ^enus farther west- 

 ward in the sandy or desert rej2,ions. Soon after passiufi; the !)8th 

 meridian we find Astragalus moUissitnus Torr. and A. lotijiorus Hook, 

 taking the place of other species of the genus, and they finally become 

 the dominant astragali of southwest Kansas, These species are well 

 known to be quite hairy. In my own experiences the latter s]>e(ties is 

 almost invariably the only one of the genus found in sand hills. Ah- 

 tragaliis pectinatus Uou^^]. and A. pictiis Gmy^var. Jili/oHns Gray, species 

 with very narrow or finely dissected leaves, and A. Farrgi Gray, a 

 very hairy species, also become quite common, especially in eastern 

 Colorado. Lepachys T<igetes Gray becomes dondnant in place of L. 

 cohimnariH Torr, and Gray in extreme southwestern ICansas, and Oxyba- 

 pints Jiiisiitus Sweet replaces largely the other oxybaphi in tlie Nentral 

 Strip. iiaura vUlosa Torr, already begins to replace other gauras iu 

 sand hills at Guthrie, Okla., and becomes qnite common farther west- 

 Avard, i^olanum el(cagni folium C'av. becomes the doini tiant member of its 

 genus in southwest Kansas and Xeutral Strip. It lias very much thick- 

 ened whitish woolly leaves and ei)idermis. It also takes the place of 

 ISolanum rosti-atum Dnnal in furnishing food for great numbers of the 

 Colorado potato beetle in Barber C<Hinty, Kans. Oenothera albieanlis 

 Nutt,, with sparsity of leaves and much-thickened stem and leaves, and 

 Oe. pinnatifida. Nutt., with finely divided leaves and hairy all over, be- 

 come <'onim(Mi in place of others of this genus in southwest Kansas and 

 southwestward, (hdllnrdia pinnatifida Torr,, almost before one recog- 

 nizes the fact, appears in place of (J. pulekella Foug., as the two species 

 resemble each other very much, but the foi iner is really mtnv ashy 

 pubescent, with leaves usually more tinely tlivided, Artemiaia, fillfolia 



