25. Prunus fremontii S. Watson in W. H. Brewer et al., Bot. California. 2: 442. 1880.
Prunus eriogyna S. C. Mason
Shrubs, suckering unknown, ˂much branched˃, 10–40 dm, thorny. Twigs with axillary end buds, glabrous. Leaves deciduous; petiole 1–7 mm, glabrous, eglandular; blade elliptic, ovate, or suborbiculate, 0.6–3 × 0.5–2 cm, base obtuse to rounded, subcordate, or truncate, margins obscurely crenulate, crenulate-serrulate, or serrate, teeth blunt, glandular, apex usually obtuse to rounded, sometimes emarginate, surfaces glabrous. Inflorescences 1–3-flowered, umbellate fascicles. Pedicels 2–12 mm, glabrous. Flowers blooming at leaf emergence; hypanthium campanulate, 2–4 mm, glabrous externally; sepals erect-spreading, semicircular to ovate, 1.2–4 mm, margins glandular-toothed, ˂ciliate˃, abaxial surface glabrous, adaxial hairy; petals usually white, sometimes pinkish rose, elliptic, obovate, or suborbiculate, 3–10 mm; ovaries hairy. Drupes yellowish, ellipsoid-ovoid, 8–15 mm, densely puberulent; mesocarps leathery to dry (splitting); stones ovoid, ± flattened.
Flowering Jan–Mar; fruiting Apr–Jun. Dry, sandy or rocky slopes, canyons, desert, chaparral, pinyon-juniper woodlands; 200–1500 m; Calif.; Mexico (Baja California).
Prunus fremontii is known only from the western edge of the Sonoran Desert.