2. Wislizenia palmeri A. Gray, Proc. Amer. Acad. Arts. 8: 622. 1873.
Wislizenia divaricata Greene; W. fruticosa Greene; W. mamillata Rose ex Greene; W. refracta Engelmann var. mamillata (Rose ex Greene) I. M. Johnston; W. refracta subsp. palmeri (A. Gray) S. Keller; W. refracta var. palmeri (A. Gray) I. M. Johnston
Subshrubs or shrubs, 50-200 cm. Stems glabrous or glabrate. Leaves: petiole 0.1-2.1 cm; leaflets 3 proximally, 1 distally, gray-green to green, blade ovate to obovate, 0.6-4 × 0.4-2 cm, 3-8(-12) times as long as wide, margins entire, apex emarginate to rounded. Racemes 1-1.5 cm (2-3 cm in fruit). Flowers: sepals green, ovate, 0.5-1.7 × 0.4-1.1 mm, less than 1.75 times as long as wide, margins entire, glabrous; petals yellow, oblong, 2.5-6.3 × 1-2.5 mm; stamens yellow, 4-10 mm; anthers (1-)1.5-2.5 mm; gynophore 5 mm in fruit, usually longer than pedicel. Schizocarps 1-5.6 × 1 mm. Seeds 0.5 × 0.3 mm. 2n = 40.
Flowering and fruiting year-round. Sandy washes, coastal dunes, saline flats, desert scrub; 100-500 m; Ariz., Calif.; Mexico (Baja California, Baja California Sur, Sonora).
Essentially a Mexican species, Wislizenia palmeri occurs in the flora area in Riverside and San Diego counties in California, and in Organ Pipe National Monument in southern Arizona.