Orobanche robbinsii

Plants simple, sometimes few-branched from base, 4–15(–26) cm, stout, base enlarged in robust specimens. Roots usually relatively conspicuous, slender, unbranched or with short bifurcations. Leaves numerous, appressed; blade broadly rounded or deltate, 3–8 mm, margins entire or erosulate, apex rounded to subacute, surfaces glabrous. Inflorescences compact corymbs (sometimes subracemose in robust specimens), pallid, usually infused with purple, often branched, densely glandular-puberulent; flowers numerous; bracts erect to slightly reflexed, ± lanceolate to oblanceolate, 5–10 mm, apex retuse or erosulate, sometimes obtuse to acute, glandular-pubescent. Pedicels 2–10 mm (to 35 mm proximally), shorter than plant axis; bracteoles 2. Flowers: calyx pallid to dark purple, weakly bilaterally symmetric, 6–14 mm, deeply divided into 5 subequal lobes, lobes subulate to narrowly spatulate, densely glandular-pubescent; corolla (8–)15–25(–30) mm, tube white to cream, sometimes pale purplish tinged distally, sometimes with purple veins, slightly constricted above ovary, slightly dilated distally, straight or ± curved forward, glandular-puberulent; palatal folds prominent, cream to lemon, glabrous; lips white to cream, sometimes purplish tinged distally (especially internally and on adaxial lip), sometimes with purple veins, abaxial lip erect to slightly spreading, 4–6(–9) mm, lobes oblong to oblong-ovate, apex rounded to truncate, adaxial lip erect to barely spreading, 4–6(–9) mm, lobes oblong to lanceolate, apex rounded to truncate, sometimes shallowly emarginate; filaments glabrous at base, anthers included or barely exserted, glabrous or with few long hairs. Capsules ovoid to cylindric-ovoid, 8–10 mm. Seeds 0.3–0.5 mm. 2n = 48.

Phenology: Flowering Apr–Jul.
Habitat: Rocky seaside bluffs, ancient shell mounds and sand dunes, eroding cliff slide areas.
Elevation: 0–100 m.

Distribution

• Generated Map
• Legacy Map

Calif.

Discussion

Orobanche robbinsii is distributed from Marin to San Luis Obispo counties. It is parasitic on Eriophyllum staechadifolium, with single reports on Artemisia pycnocephala (Asteraceae) and Phacelia californica (Hydrophyllaceae).

Selected References

None.

Lower Taxa

None.