SOME ROCKY MOUNTAIN ASTERS. 217 
far-western homologue, A. commutatus, Gray, though the 
bracts in our plant are in no wise spreading. 
A. SPITHAMJEUS. Stems several, 5 to 8 inches high, from 
horizontal rootstocks, erect, rigid, rather densely leafy up to 
the fastigiate-corymbose inflorescence of 3 to 7 above mid- 
dle-sized heads, both stems and foliage firm and even rigid; 
all the leaves oblanceolate, acute, entire, sharply scabrous- 
ciliate, the petiolar base hispid-ciliate, the upper surface 
strigose-scabrous, the lower glabrous: involucres campan- 
ulate, 4 inch high, their bracts strongly imbricated in 
about 4 series, mainly cartilaginous and colorless except as 
to the elliptic green tips, all acute, sparsely strigose on the 
back and marginally ciliolate: rays 20 or more, deep pur- 
ple; central flowers of the head sterile, achenes of the 
several fertile series red-purple, compressed but rather 
prominently 5-angled, the whole surface with a sparse ap- 
pressed white pubescence. 
A fine species, known only in specimens collected by 
myself on a dry mountain side above Gunnison, Colorado, 
10 Sept, 1890. I at the time mistook it for a Machzran- 
thera, misled by its rigid leafiness, much imbricated involu- 
cre and rich purple rays; but it is a very genuine Aster. 
A. FULCRATUS. Stems low, slender, decumbent, numer- 
ous, from a loose but extensive system of slender horizontal 
rootstocks and partly subterranean stolons, the leaves ter- 
minating the latter small and from obovate to spatulate - 
oblong; those of the red-purple, white-puberulent proper 
stems linear and lance-linear, 2 to 4 inches long, 1-nerved, 
all entire and glabrous: heads large, solitary at the ends of 
the smaller stems, few and racemose or subcorymbose on the 
taller ones, but these only a foot high: involueres turbinate 
