70.
Symphyotrichum spathulatum
(Lindley) G. L. Nesom, Phytologia. 77: 291. 1995.
Western mountain aster
Aster spathulatus
Lindley in W. J. Hooker, Fl. Bor.-Amer. 2: 8. 1834
Perennials,
20—80 cm, colonial; long-rhizomatous.
Stems
1—5+, ascending to erect, glabrous or sparsely puberulent.
Leaves
thin, margins entire, apices acute, faces glabrous or sparsely puberulent; basal persistent, petiolate, blades narrowly elliptic to obovate, 50—150 × 3—15 mm, attenuate, margins entire; proximal cauline sessile or subpetiolate, blades linear to narrowly elliptic, 50—150 × 2—15 mm, bases attenuate or cuneate; distal sessile, blades 30—60 × 2—10 mm, reduced distally, bases cuneate to rounded.
Heads
in corymbiform to paniculiform arrays, branches usually few.
Peduncles
sparsely hairy, bracts 0—3+.
Involucres
campanulate, 5—10 mm.
Phyllaries
in 3—5 series, narrowly oblong or linear (outer) to linear (inner), unequal, bases indurate, margins entire, green zones elliptic to lanceolate , apices usually acute, sometimes obtuse, faces glabrous or ± puberulent.
Ray florets
15—40; corollas violet, laminae 9—15 × 1—2 mm.
Disc florets
30-80(—100); corollas yellow, sometimes becoming reddish, 4.5—6 mm, lobes triangular, 0.5—1 mm.
Cypselae
brown, cylindric to obovoid, not compressed, 2.5—3.5 mm, ± 4-nerved, faces hairy;
pappi
whitish, 5—7 mm.
Varieties 3 (3 in the flora): w North America, nw Mexico.
Symphyotrichum spathulatum
is a variable species, widespread in montane regions of western North America. It hybridizes with
S. eatonii, S. foliaceum
, and
S. hendersonii
.
