Asterothamnus in Flora of China @ efloras.org

127. Asterothamnus Novopokrovsky, Bot. Mater. Gerb. Bot. Inst. Komarova Akad. Nauk S.S.S.R. 13: 331. 1950.

紫菀木属 zi wan mu shu

Subshrubs; rhizome woody. Stems numerous, erect or ascending, strongly branched, white to gray tomentose or arachnoid or villosulous to villous or villosulous-tomentose. Leaves sessile, small, crowded, subleathery, margin often revolute, 1-veined. Capitula radiate or sometimes discoid, solitary at ends of stems or branches or 3-5 in corymbiform synflorescences. Involucre broadly campanulate or subhemispheric; phyllaries 3- or 4-seriate, imbricate, usually unequal, often apically purple tinged, leathery, margin broad, scarious, erose, whitish, midvein distinct, brownish or reddish, apex acute. Receptacles ± flat, alveolate, irregularly denticulate. Florets fertile. Ray florets female, blue, light violet, or whitish pink; disk florets bisexual, yellow, turning pink, limb funnelform to narrowly campanulate, 5-lobed, lobes lanceolate; anther base obtuse, appendage lanceolate; style branch tips triangular. Achenes oblanceoloid, ± compressed, 2- or 3-ribbed, ± densely strigose. Pappus white, yellowish, reddish, or dirty white, barbellate, equaling disk corollas, in 3 or 4 series, outermost few, short, thin, outer and inner long, acute, innermost few, ± slightly clavate.

About seven species: C Asia; five species in China.

1 Leaves 1-2 mm wide, linear or linear-oblong (2)

+ Leaves 2-4 mm wide, oblong to oblong-lanceolate or oblong-oblanceolate (3)

2 (1) Stems branched throughout, densely white or cinnamon villosulous; leaves linear, 10-15(-20) × 1-1.5 mm; capitula usually radiate, sometimes discoid, peduncles slender; phyllary apex greenish or white, rarely purplish. 2 A. fruticosus

+ Stems branched in lower part only, gray-white tomentulose; leaves linear-oblong to linear, (8-)12-15 × 1.5-2 mm; capitula radiate, peduncles rather thick; phyllary apex purplish red. 3 A. centraliasiaticus

3 (1) Leaves oblong-oblanceolate, 6-8 × 2-3(-4) mm, apex shortly acuminate; bark at stem base reddish brown. 1 A. alyssoides

+ Leaves oblong or oblong-lanceolate to oblong-oblanceolate, 10-25 × 2-4 mm, apex obtuse to ± acute, mucronate; bark at stem base yellow-brown (4)

4 (3) Leaves 10-12(-20) mm; phyllaries densely gray-white cottony, apex shortly acuminate to ± obtuse. 4 A. molliusculus

+ Leaves 15-25 mm; phyllaries gray-white tomentulose, apex acuminate. 5 A. poliifolius

Lower Taxa