Plants ± thinly arachnoid-sericeous. Stems usually 1, erect. Capitular leaves: longest mostly 14-25 mm, lengths 3-6 times widths. Heads ovoid, largest 9-14 mm, ± sericeous. Receptacles deep-ly lobed. Pistillate paleae ± cylin-dric, lengths mostly 3.5-6 times longest diams.; wings ± median. Flowering and fruiting May-mid Jun. Drying margins of vernal pools, seasonally moist flats; 10-100(-500) m; Calif. Variety multiflorus is known from the San Francisco Bay area and adjacent Central Valley delta and may soon warrant conservation concern. Its deeply lobed receptacles, each lobe bearing a set of staminate florets, appear to represent fusion of multiple heads into second-order heads (A. Cronquist 1950). Less fusion occurs in plants intermediate with var. brevissimus.

Variety multiflorus shares traits with Psilocarphus elatior. An Idaho specimen from within the range of P. elatior was cited (but not mapped) as P. brevissimus var. multiflorus by A. Cronquist (1950); it was probably either mislabeled or from an introduction that did not persist.