Symphyotrichum hendersonii

(Fernald) G. L. Nesom

Phytologia 77: 283. 1995.

Common names: Henderson’s aster
Endemic
Basionym: Aster hendersonii Fernald Bull. Torrey Bot. Club 22: 273. 1895 (as hendersoni)
Synonyms: Aster foliaceus subsp. lyallii (A. Gray) Cronquist
Treatment appears in FNA Volume 20. Treatment on page 534. Mentioned on page 477.

Perennials, 70–150 cm, colonial; long-rhizomatous. Stems 1–5+, ascending to erect, glabrous or puberulent, especially distally. Leaves thin, margins entire, apices acute, faces glabrous or scabridulous; basal persistent or withering by flowering, petiolate, blades oblanceolate, 50–150 × 10–20 mm, bases attenuate or cuneate; proximal cauline sessile, blades elliptic to oblanceolate, 80–200 × 10–25 mm, bases cuneate, auriculate; distal sessile, 40–80 × 7–20 mm, reduced distally. Heads in paniculiform arrays, branches numerous, 10–45 cm. Peduncles sparsely to densely hairy, bracts 3–10, acute, lanceolate to linear, bases auriculate. Involucres campanulate, 5–10 mm. Phyllaries in 4–5 series, narrowly oblong or linear (outer) to linear (inner), unequal, bases scarious, margins entire, sometimes proximally ciliate, green zones linear, apices acute, faces glabrous. Ray-florets 25–45; corollas violet, laminae 9–15 × 1–2.5 mm. Disc-florets (50–) 70–80; corollas yellow, 5–6 mm, lobes triangular, 0.5–0.8 mm. Cypselae brown, cylindric to obovoid, not compressed, 3–3.5 mm, 3–4-nerved, faces hairy; pappi white, 4.5–5 mm. 2n = 16, 32.


Phenology: Flowering Jul–Aug.
Habitat: Meadows, stream banks, forest openings
Elevation: 1000–1500+ m

Distribution

V20-1190-distribution-map.gif

Calif., Idaho, Mont., Oreg., Wash.

Discussion

Symphyotrichum hendersonii is concentrated in north-central Idaho and adjacent Montana and Washington, with possibly outlying populations in the Siskiyou Mountains of southwestern Oregon and adjacent California. It is in some respects intermediate between S. spathulatum and S. cusickii; forms transitional to both of these species occur.

Selected References

None.

Lower Taxa

None.

"thin" is not a number.

not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +
indeterminate +  and determinate +
Luc Brouillet +, John C. Semple +, Geraldine A. Allen +, Kenton L. Chambers +  and Scott D. Sundberg† +
(Fernald) G. L. Nesom +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
auriculate +, cuneate +, attenuate +  and oblanceolate +
scarious +
10mm;20mm +
Aster hendersonii +
8 cm80 mm <br />0.08 m <br /> (20 cm200 mm <br />0.2 m <br />) +
elliptic;oblanceolate +
10mm;25mm +
rugulose +  and muricate +
lanceolate +  and linear +
barbellulate +  and barbellate +
sessile +  and petiolate +
Henderson’s aster +
not 2-lipped +  and actinomorphic +
yellow +  and violet +
at maturity , more or less ampliate , tubes usually shorter +
0.5 cm5 mm <br />0.005 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 +
4 cm40 mm <br />0.04 m <br /> (8 cm80 mm <br />0.08 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (?) +  and 2 cm20 mm <br />0.02 m <br /> (?) +
Calif. +, Idaho +, Mont. +, Oreg. +  and Wash. +
1000–1500+ m +
hairy +  and glabrous +
scabridulous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Meadows, stream banks, forest openings +
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 (?) +
1mm;2.5mm +
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 +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Flowering Jul–Aug. +
linear to linear +  and oblong +
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 +
1 +  and 5 +
appendaged +  and truncate +
papillate +  and smooth +
Aster foliaceus subsp. lyallii +
Symphyotrichum hendersonii +
Symphyotrichum sect. Occidentales +
species +
funnelform-campanulate +  and cylindric +
at maturity , more or less ampliate , tubes usually shorter +
ampliate +
70 cm700 mm <br />0.7 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
tree +, shrub +  and subshrub +
usually diamond-shaped +  and lanceolate +