404. Brickelliastrum R. M. King & H. Robinson, Phytologia. 24: 63. 1972.
[Generic name Brickellia and Latin -astrum, indicating inferiority or an incomplete resemblance]
Guy L. Nesom
Perennials or subshrubs, 30–80+ cm (plants not viscid). Stems decumbent to erect, much branched from bases. Leaves cauline; mostly opposite (distal sometimes alternate); petiolate; blades usually 3-nerved, deltate to ovate, margins crenate-dentate, faces pubescent or glabrous, sometimes gland-dotted. Heads discoid, in loose, corymbiform to paniculiform arrays. Involucres ± campanulate, 4–7 mm diam. Phyllaries persistent, 20–25 in 3–4 series, 2- or 4-nerved, lance-ovate to lanceolate, unequal (herbaceous to chartaceous). Receptacles convex, epaleate. Florets 25–35; corollas white or yellowish white, throats funnelform (lengths 2.5–4 times diams.); styles: bases not enlarged, glabrous, branches narrowly clavate. Cypselae prismatic, 5(–7)-ribbed, puberulent; pappi readily falling or fragile, of ca. 25 barbellate bristles in 1 series. x = 10.
Species 2 (1 in the flora): sw United States, n Mexico.
B. L. Turner (1988c, 1994c, 1996+) placed Brickelliastrum, Asanthus, and the Mexican genus Dyscritogyne R. M. King & H. Robinson within Steviopsis R. M. King & H. Robinson. All four are essentially segregates of Brickellia, distinguished especially by their lack of pubescent swellings at bases of stylar shafts. As noted by Turner, this aggregate forms a heterogeneous group; the finer division is followed here until further evidence indicates a better taxonomic disposition.