[For Lloyd Herbert Shinners, 1918–1971, botanist, long at Southern Methodist University, founder of the journal Sida]

Guy L. Nesom

Perennials, 10–30 cm (aquatic). Stems ascending, unbranched or branched (rooting at proximal nodes). Leaves cauline; opposite; sessile; blades 1- or 3-nerved, broadly oblanceolate or 3-lobed, ultimate margins coarsely toothed, faces sometimes pilose and glabrescent or glabrous, gland-dotted. Heads discoid, borne singly. Involucres hemispheric or broader, 6–9 mm diam. Phyllaries persistent, 25–30 in 2–3+ series, not notably nerved, ovate to lanceolate or linear, ± equal (herbaceous to membranous). Receptacles convex to conic, epaleate (warty). Florets 75–100+; corollas white, throats broadly campanulate (notably wider than tubes, lengths ca. 1 times diams.); styles: bases not enlarged, glabrous, branches linear-filiform. Cypselae prismatic, 4–5-ribbed, sparsely gland-dotted and sparsely hairy (hairs forked); pappi 0. x = 15?

Species 1: Texas, n Mexico.

Lower Taxon

• Shinnersia rivularis (A. Gray) R. M. King & H. Robinson