Herbs, perennial or biennial, usually short-lived, succulent, glabrous. Roots fibrous or tuberous. Stems: flowering shoots annual, prostrate to ascending. Leaves rosulate, or cauline and alternate or opposite, sessile; stipules absent; blade linear, ± grooved, ± triangular in cross section. Inflorescences axillary, flowers solitary; peduncle erect, 10(-12) cm; bracts absent. Flowers showy, tubular, 5-13 cm diam.; calyx lobes 5, green, unequal, wider at base, apex cylindric, basal margins of inner 3 lobes papery; petals (including petaloid staminodia) 250, distinct, free, yellow; nectary present; stamens 500+, distinct; filament bases hairy; pistil 10-25-carpellate; ovary inferior, connate in proximal ¹/2, 10-25-loculed; placentation parietal with 2 seed pockets on outer wall of each locule; styles absent; stigmas 10-25, filiform. Fruits capsules, conic; valves 10-25, opening but not spreading when moistened, finally separating into 10-25 segments. Seeds 75-200, spheric, margins keeled, smooth; arils absent.

Herrea Schwantes is closely related to Conicosia; it has been wrongly cited for California. Conicosia and Herrea share a number of characteristics; they are distinguished by the dissepiments (partitions) of the fruits, which reach to the apex of the valves in Herrea and halfway up the valves in Conicosia. In Herrea, the capsule splits into many segments without a firm central column; in Conicosia, the capsule does not separate into many segments, or at least not until decaying away. Herrea is included in Conicosia by H. D. Ihlenfeldt and M. Gerbaulet (1990). In general, conicosias do well in poor, sandy soils (U. Van der Spuy 1971). They grow readily and naturalize in sandy dune habitats in coastal California.