Leaves: basal often withered by flowering, cauline 2-5 cm × 0.3-1.5 mm. Corollas 5-6 mm. Cypselae ca. 3 mm; pappi: muticous scales ca. 0.5 mm; aristate scales ca. 5 mm. 2n = 20.

Flowering (Jan-)Feb-Mar(-Apr). Gravelly and sandy washes and other alluvium, rocky hillsides, sandy flats, lava, desert scrub, creosote bush flats; 10-700 m; Calif.; Mexico (Baja California, Baja California Sur, Sonora).

Malperia tenuis is recognized by its annual duration, linear leaves densely arranged along stems or concentrated near bases of stems, loosely arranged heads, and pappi of two kinds of scales.