Streptanthus howellii

S. Watson

Proc. Amer. Acad. Arts 20: 353. 1885.

EndemicConservation concern
Synonyms: Cartiera howellii (S. Watson) Greene
Treatment appears in FNA Volume 7. Treatment on page 716. Mentioned on page 701, 732.

Perennials; (caudex simple or branched); (glaucous), glabrous. Stems usually unbranched, rarely branched distally, 3–8 dm. Basal leaves (soon withered); not rosulate; petiolate; blade (somewhat fleshy), similar to cauline. Cauline leaves (petiolate); blade broadly spatulate-obovate to suborbicular, or (distally) narrowly oblong-oblanceolate to linear, 1.5–10 cm × 5–45 mm, base (distally) cuneate to attenuate, not auriculate, margins entire, repand, or obtusely dentate, (entire distally). Racemes ebracteate, (lax). Fruiting pedicels divaricate to ascending, (straight), 7–17 mm. Flowers: calyx subcampanulate; sepals purplish, oblong, 5–8 mm, not keeled; petals maroon to purple, 8–12 mm, blade 3–5 × 0.5–1 mm, margins not crisped, claw 5–7 mm, wider than blade; stamens in 3 unequal pairs; filaments (distinct): abaxial pair 5–6 mm, lateral pair 4–5 mm, adaxial pair 6–7 mm; anthers (all) fertile, 3–3.5 mm; gynophore 0.5–5 mm. Fruits divaricate-ascending, smooth, straight to slightly curved inwards, flattened, 5.5–12 cm × 2.5–3.2(–3.5) mm; valves each with prominent midvein; replum straight; ovules 24–44 per ovary; style 0.3–3 mm; stigma subentire. Seeds broadly oblong to suborbicular, 3–4 × 2–3 mm; wing 0.5–1.1 mm wide, continuous. 2n = 28.


Phenology: Flowering Jun–Jul.
Habitat: Dry serpentine slopes and ridges in open conifer-hardwood forests
Elevation: 600-800 m

Discussion

Of conservation concern.

Streptanthus howellii is known from the Klamath Mountains in California (Del Norte and Siskiyou counties) and Oregon (Curry and Josephine counties).

Selected References

None.

Lower Taxa

None.