Xanthisma spinulosum var. glaberrimum
Sida 20: 1408. 2003.
Perennials, 20–50 cm, often woody at base. Stems stiffly erect, branched in distal 1/3; mid internodes 2–5 mm. Leaves numerous, strictly ascending, not reduced distally, margins pinnatifid, lobes oblong-lanceolate to triangular, 2–7 mm, faces usually glabrous, sometimes lightly tomentose, eglandular. Heads 2–10+, (subsesssile) usually clustered. Peduncles relatively terminal and lateral, 0.5–2 cm. Involucres 8–15 mm wide. 2n = 8, 16.
Phenology: Flowering spring–fall.
Habitat: Sandy to gravelly prairies, hillsides, and roadsides
Elevation: 800–1400 m
Distribution
Colo., Iowa, Kans., Nebr., N.Mex., N.Dak., Okla., Tex., Wyo.
Discussion
G. L. Nesom (2003) recognized Xanthisma spinulosum var. glaberrium at species level, as it occurs sympatrically with variety spinulosum in the Texas panhandle, where the two taxa behave like biological species; on the eastern plains of Colorado, however, hybridization and autoploidy have been documented (D. P. Hauber 1986).
Selected References
None.