292 BOTANICAL.GAZETTE [OCTOBER 
occurring in the open association, the Asters become quite noticeable 
though they are all of a lower layer than S. rigida. The silky Aster, 
A. sericeus, usually of low abundance and general occurrence, fre- 
quently becomes copious on bunch-grass knolls, there forming very 
distinct associations. Rising some 50°", with numerous spreading 
branches terminating in prominent heads (2 to 3°™ in diameter) with 
numerous violet rays, and bearing abundant leaves which are densely 
covered above and below with a silvery-white silky pubescence, this 
Aster is always a conspicuous element of the middle and late autumnal 
aspect. Its achenes are equipped with a medium pappus. It is 
a perennial from a thickened rootstock. 
The two other Asters are similar in frequency and abundance mM 
A. sericeus, but never attain its prominence. Of these A: oblongt- 
folius always occurs with A. sericeus in the open association. With 
us it always remains depauperate. Seldom more than 30% high, 
it is ever inconspicuous, though its bluish rays make it noticeable at 
short range, since it is usually overshadowed by A. sericeus. It ” a 
perennial and is wind-distributed; a copious pappus serves to bring 
about a general invasion, which, as in the other Asters, seems 10 be 
coupled with a high percentage of establishment, especially 1 ee 
open xerophytic associations of the formation. The dense-flowered 
aster, A. multiflorus, occurs perhaps more frequently but less abun- 
dantly than the former, and is similarly a xerophyte of the open wae 
ciation, in which situations it never reaches other than 4 redue h 
stature. However, its bushy spreading branches, thickly ager om 
numerous small white heads, invariably make it more eeu 
than A. oblongifolius, particularly when it occurs in pa px tet 
seems to work down upon the lower slopes, here attaining . sa 
stature and abundance as well as a greater prominence in anthies 
All the Asters are perennial from rootstocks and form small 
Tosettes, and are wind-disseminated. - 1 from & 
The hairy prairie clover, Kuhnistera villosa, is a perennial ched 
deep tuberous ‘root. Densely silky pubescent, abundantly bran 5) of 
and terminating in cylindrical clustered spikes (3 © és _ -cted 
Tos¢-purplish flowers, it is in itself quite conspicuous, but its sos the 
frequency and rare abundance make it rarely a tonal com 
formation. In the bunch-grass formation it becomes, W! 
