Symphyotrichum spathulatum

(Lindley) G. L. Nesom

Phytologia 77: 291. 1995.

Common names: Western mountain aster
Basionym: Aster spathulatus Lindley in W. J. Hooker, Fl. Bor.-Amer. 2: 8. 1834
Treatment appears in FNA Volume 20. Treatment on page 534. Mentioned on page 477, 537, 538.

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.

Distribution

V20-1191-distribution-map.gif

Alta., B.C., N.W.T., Calif., Colo., Idaho, Mont., N.Mex., Nev., Oreg., Utah, Wash., Wyo., nw Mexico

Discussion

Varieties 3 (3 in the flora).

Symphyotrichum spathulatum is a variable species, widespread in montane regions of western North America. It hybridizes with S. bracteolatum, S. foliaceum, and S. hendersonii.

Selected References

None.

Key

1 Leaves linear Symphyotrichum spathulatum var. yosemitanum
1 Leaves narrowly elliptic to oblanceolate > 2
2 Plants 40–80 cm; heads usually 10–50 Symphyotrichum spathulatum var. intermedium
2 Plants 20–50(–60) cm; head usually 3–10 Symphyotrichum spathulatum var. spathulatum

"thin" is not a number.

not tailed +, rounded +  and obtuse +
distinct +
obtuse;acute;acute +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
corymbiform +  and paniculiform +
indeterminate +  and determinate +
Luc Brouillet +, John C. Semple +, Geraldine A. Allen +, Kenton L. Chambers +  and Scott D. Sundberg† +
(Lindley) G. L. Nesom +
spatulate;oblanceolate elliptic or ovate +
cuneate +  and rounded +
indurate +
Aster spathulatus +
1-nerved +, subsessile +, sessile +  and petiolate +
elliptic +  and linear to narrowly +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
attenuate;narrowly elliptic;obovate +
reduced +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
rugulose +  and muricate +
barbellulate +  and barbellate +
sessile +  and petiolate +
Western mountain aster +
not 2-lipped +  and actinomorphic +
reddish +, yellow +  and violet +
at maturity , more or less ampliate , tubes usually shorter +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
strigillose +  and glabrous +
not compressed +, cylindric +  and obovoid +
fertile +  and bisexual +
fertile +  and bisexual +
Alta. +, B.C. +, N.W.T. +, Calif. +, Colo. +, Idaho +, Mont. +, N.Mex. +, Nev. +, Oreg. +, Utah +, Wash. +, Wyo. +  and nw Mexico +
hairy +, puberulent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
disciform +  and radiate +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.4 cm4 mm <br />0.004 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
campanulate +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
1.8 cm18 mm <br />0.018 m <br /> (2.1 cm21 mm <br />0.021 m <br />) +
2 (?) +  and 5 (?) +
sessile +  and petiolate +
cauline +  and basal +
decurrent +
triangular +
not +  and hyaline +
ciliate +  and scabrous +
coarsely serrate +  and crenate or entire +
2-carpellate +
persistent +
25 +  and 40 +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
linear to linear +  and oblong +
subpetiolate +  and sessile +
styliferous +, neuter +  and pistillate +
bearing subulate enations +, hairy +  and bristly +
flat;slightly convex +
exalbuminous +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.1mm;0.2mm +
branched +  and simple +
ascending +  and erect +
puberulent +  and glabrous +
1 +  and 5 +
appendaged +  and truncate +
papillate +  and smooth +
Aster sect. Heterastrum +  and Aster subg. Symphyotrichum +
Symphyotrichum spathulatum +
Symphyotrichum sect. Occidentales +
species +
funnelform-campanulate +  and cylindric +
at maturity , more or less ampliate , tubes usually shorter +
ampliate +
20 cm200 mm <br />0.2 m <br /> (80 cm800 mm <br />0.8 m <br />) +
tree +, shrub +  and subshrub +
elliptic +  and lanceolate +