18. Symphyotrichum concolor (Linnaeus) G. L. Nesom, Phytologia. 77: 278. 1995.
Eastern silvery aster
Aster concolor Linnaeus, Sp. Pl. 2: 874. 1753; Lasallea concolor (Linnaeus) Semple & Brouillet; Virgulus concolor (Linnaeus) Reveal & Keener
Perennials, 30–80 cm, cespitose; with cormoid, woody caudices. Stems 1–10+, ascending to erect (light to dark brown), glabrous or densely canescent distally. Leaves (green to graysih) soft to firm; basal withering by flowering, sessile, blades (1–3-nerved) elliptic-lanceolate, 10–43 × 5–15 mm, bases attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices acute to obtuse, faces silvery silky-pilose to sparsely pilose; proximal cauline withering by flowering, sessile, blades oblanceolate, 20–35 × 5–15 mm, bases rounded, subclasping, margins entire, scabrous to silky-pilose, apices acute to obtuse, cuspidate mucronate, faces ± densely silky; distal sessile, blades usually oblong to lanceolate, rarely ovate, 9–15 × 1.8–5 mm, reduced distally, bases cuneate, margins entire, apices acute, mucronate, faces ± densely silky or sparsely strigose, sometimes glabrate (var. devestitum). Heads in narrow, paniculiform (virgate) arrays (1–3(–5) per branch). Peduncles densely hairy, bracts becoming linear, grading into phyllaries. Involucres campanulate to narrowly campanulate, 5–7 mm. Phyllaries in 3–5 series, appressed, lanceolate-oblong, strongly unequal, bases (tan) ± indurate, margins scarious proximally, green distally, green zones restricted to apex, obscured by hair, apices usually acute, sometimes acuminate, usually mucronate, sometimes subspinulose, faces ± densely silky. Ray florets 8–12; corollas rose-purple, rarely white, laminae 4–9 × 1–1.5 mm. Disc florets (9–)11–17(–21); corollas pink turning purple, 4.5–6 mm, tubes shorter than narrowly funnelform throats (thinly puberulent), lobes triangular, 0.4–0.7 mm. Cypselae obovoid, not compressed, 2.5–3.5 mm, 7–10-nerved, faces densely strigose; pappi tan, (3.5–)4–6 mm.
Varieties 2 (2 in the flora): e United States.