Asteraceae (tribe Heliantheae) subtribe Marshalliinae
Perennials, (10–)20–80(–120) cm. Leaves mostly basal and/or cauline; alternate; petiolate or sessile; blades 1- or 3-nerved, mostly elliptic, linear, oblanceolate, ovate, or spatulate, margins entire, faces usually glabrous, gland-dotted. Heads discoid, borne singly or in open, corymbiform arrays. Calyculi 0. Involucres turbinate to obconic or hemispheric. Phyllaries persistent, 10–20 in 2+ series (distinct, narrowly oblong to linear-elliptic or lance-subulate, subequal, herbaceous, basally thickened-keeled, sometimes callous- or scarious-margined). Receptacles convex to conic, paleate (paleae mostly linear to filiform, herbaceous). Ray florets 0. Disc florets (20–)45–90(–160+), bisexual, fertile; corollas lavender, pink, purple, or white, tubes much longer than to equaling funnelform throats, lobes 5, lance-linear to linear-oblong; anther thecae cream to purple; stigmatic papillae in 2 lines. Cypselae stoutly obpyramidal, 5(–6)-angled, hairy; pappi persistent, of 5(–6) lance-deltate to lance-attenuate, scarious (often hyaline) scales.
c, e United States.
Genus 1, species 7 (7 species in the flora).
Marshalliinae was related to epaleate subtribes of Heliantheae by H. Robinson (1981), rather than to Eupatorieae, as suggested by T. F. Stuessy (1977) and by B. L. Turner and A. M. Powell (1977). B. G. Baldwin and B. L. Wessa (2000) suggested that Marshallia may be sister to Gaillardiinae and results presented by Baldwin et al. (2002) showed Marshallia nested in Gaillardiinae, near Pelucha S. Watson, Psathyrotes, and Trichoptilium.