186 DESCRIPTION OF ASTER; DIVARICATI 
N. Y. vic., Tarrytown, Sleepy Hollow, summit, Se. 24,’98. Yonkers, Bryn 
Mawr Park, Se. '96—'99. Mosholu, at full height June 26, 1905. 
N. J., Palisades, Se. '97, '98. 
A, circularis differs from obolarian plants of A. divaricatus in 
its closer, i ie teeth, firmer texture, and deeper and more per- 
sistent sinu 
From A divaricatus curtifolius it differs in its thinner, smaller 
leaves, narrow bracts, and more continuous sinus, short rays and 
smaller, fewer heads. 
m A. rupicola it cone in its smaller shorter leaves and 
more Biet curve-back teeth. 
From A. argillarius it differs in its more slender leaves, more 
outflung teeth, and paler bevel-tip bracts. 
All the above species make an approach to a subcircular leaf- 
form, but A. circularis approximates to it most closely. 
A. circularis is also unlike the others in having all leaves 
cordate. 
SUBDIVISION C 
Bracts lingual, sashes at tip, nearly all alike in shape, nearly 
all-over green. Sp. 22-25. 
22. Aster argillarius sp. nov. 
Small, stiff, brittle, close-clustered plants, with little ovate- 
acute subuniform leaves, little hair, almost no sinus, short petioles, 
obconic inflorescence, and lingual rounding-tipped bracts. 
Name from its partiality to clayey soil, L., argilla, clay. 
Fic. 31, plant from Palisades, N. J., Se. '97, in hb. Bz. ; e, charac- 
teristic leaf; /, a lower-leaf form; 4, an upper-leaf Fa g, radicals. 
Stem browned in half-sun, green in shade, slightly and repeat- 
edly flexed, erect, stiff and brittle, very slender and delicate in 
aspect, chiefly 1 ft. high, sometimes 1 9. 
Leaves (the cauline), very small, nearly uniform, 1 x 34 in. 
or sometimes I 14 x I in., ovate-acute, or slightly incurve-acumi- 
nate, thin, firm, of peculiar silken texture when fresh, rough when 
dry, full green, serrate with moderate straight-backed teeth, or 
with some curvescent or aquiline teeth intermixed. Sinus slight, 
rather sharp in a few lower caulines, quite open in the lowest. 
Petioles all short and slender, continuing to the first axils. 
Radical leaves when developed often form quite conspicuous 
little tufts, 3 or 4 inches removed from the stem from which their 
rootstock springs. These radicals are often 5 to 10 together, in 
size 114 x I in., oval-oblong, with small sharp sinus, with a 
shorter filiform petiole, rather dark-green, their apex acute (not 
acuminate), their teeth crenate-serrate. 
