Hesperolinon (A.Gray) Small, 1907h: 84 .

Type:— Hesperolinon californicum (Benth.) Small, N. Amer. Fl. 25: 86. 1907.

Description: — Herbs, annual, thin, glabrous, occasionally pubescent or puberulent; stems erect or extended, sometimes slightly decumbent, not branched or branched from the base or from the inflorescence, glabrous or pubescent. Leaves entire or with marginal glands; basal leaves arranged in whorls of 4, distal leaves opposite or alternate; sessile or subsessile, with or without stipular glands. Inflorescence terminal, in a cymose panicle, sometimes condensed. Flowers with 5 sepals, imbricate, connate at the base, persistent, entire or with marginal glands, glabrous or villous; petals 5, yellow, white to pink, convolute, reddish venation; presence of basal adaxial appendages, more or less conspicuous, that sometimes expand into auricles; stamens 5, staminodia absent; styles 2–3, free, stigmata capitate or subcapitate; ovary superior, 2 or 3-locular, or 4 or 6-locular due to the presence of false septa. Fruit a septicidal capsule, ovoid, dehiscent into 4 or 6 segments, glabrous; seeds 4 or 6, triangular in cross-section, brown, often with darker spots; testa mucilaginous. The genus comprises one species in Mexico, distributed in a narrow area of the state of Baja California.