Symphyotrichum subg. Ascendentes

(Rydberg) Semple in J. C. Semple et al.
in J. C. Semple et al., Cult. Native Asters Ontario, 133. 2002.
Basionym: Ascendentes Rydberg Fl. Colorado, 352, 354. 1906
Synonyms: Symphyotrichum sect. Ascendentes (Rydberg) G. L. Nesom Undefined subg. Virgulaster Semple
Treatment appears in FNA Volume 20. Treatment on page 537. Mentioned on page 466, 467.

Perennials, eglandular; rhizomatous. Stems not brittle at maturity, densely and uniformly strigose, especially distally. Leaves: basal persistent to, or withering by, flowering, petiolate, blades 1-nerved, oblanceolate, margins entire; cauline sessile or subpetiolate, blades linear, oblong, or obovate, bases attenuate or cuneate. Phyllaries usually unequal, sometimes subequal, green zones obovate to oblanceolate or elliptic (apices sometimes foliaceous, outer rarely wholly foliaceous). Rays florets (10–)14–60 in 1 series, laminae 8–13(–15) × 1–1.5(–2) mm. Disc corollas ± ampliate, throats funnelform, lobes erect. Cypselae cylindric to obovoid, not compressed, 4–7-nerved, glabrous. x = 13, 18, 21.

Distribution

w North America.

Discussion

Species 2 (2 in the flora).

G. A. Allen (1985, 1986) demonstrated the hybrid origin of the allopolyploid Symphyotrichum ascendens and S. defoliatum from members of subg. Symphyotrichum sect. Occidentales and subg. Virgulus sect. Ericoidi; a separate subgenus was erected to accommodate these inter-subgeneric allopolyploids. In 1986, Allen also identified populations with the chromosome number 2n = 42 (x = 21) in the Mount Pinos area, southern Kern and northern Ventura counties, California. These populations resulted from a cross between S. ascendens and S. spathulatum, giving rise to an allopolyploid that, though an incipient species, lacks sufficient morphologic distinction from S. ascendens or S. spathulatum to allow separate recognition. Aster subg. Ascendentes (Rydberg) Semple is an illegitimate name.

Luc Brouillet +, John C. Semple +, Geraldine A. Allen +, Kenton L. Chambers +  and Scott D. Sundberg† +
(Rydberg) Semple in J. C. Semple et al. +
Ascendentes +
w North America. +
in J. C. Semple et al., Cult. Native Asters Ontario, +
allen1985a +  and allen1986a +
Symphyotrichum sect. Ascendentes +  and Undefined subg. Virgulaster +
Symphyotrichum subg. Ascendentes +
Symphyotrichum +
subgenus +