Annuals. Stems 8–85 cm, not self-supporting, basally hairy, otherwise glabrous; branches twining. Leaves opposite proximally, alternate distally; blade linear, 5–55 × 1–4 mm, surfaces glabrous. Inflorescences axillary, flowers solitary. Pedicels 4–25 (–30) mm. Flowers cleistogamous and chasmogamous; calyx lobes equal, glandular-hairy, adaxial lobe 2.5–4 × 1–1.5 mm; corolla light purple, purple-veined, 5.5–7 mm, base barely gibbous, mouth 2–2.5 mm diam., palate purple-veined, angular, 2.5–4 mm diam., minutely papillate. Capsules globular-ovoid, 2.5–6 mm, glandular-hairy, abaxial locule with 1 pore. Seeds black, 0.6–1 mm, tuberculate. 2n = 30.

Phenology: Flowering Mar–Apr.
Habitat: Gravelly slopes.
Elevation: (0–)200–1000 m.

Distribution

• Generated Map
• Legacy Map

Ariz., Mexico (Baja California), Mexico (Baja California Sur), Mexico (Sonora)

Discussion

The only North American collections of Sairocarpus watsonii are from Organ Pipe National Monument in Pima County. Sairocarpus watsonii is similar to S. kingii, which grows farther north and has unequal sepals.

Selected References

None.

Lower Taxa

None.