Malacothamnus densiflorus

(S. Watson) Greene

Leafl. Bot. Observ. Crit. 1: 208. 1906.

Common names: Dense-flowered or yellowstem bushmallow
Basionym: Malvastrum densiflorum S. Watson Proc. Amer. Acad. Arts 17: 368. 1882
Synonyms: Malacothamnus densiflorus var. viscidus (Abrams) Kearney Malvastrum densiflorum var. viscidum (Abrams) Estes M. viscidum Sphaeralcea densiflora S. densiflora var. viscida (Abrams) Jepson
Treatment appears in FNA Volume 6. Treatment on page 284. Mentioned on page 281, 282, 285.

Shrubs, 1–2 m, branches slender, indument tawny, sparse to moderately dense, stellate hairs sessile or subsessile, usually overlain by 1–2–few-armed, bristly hairs to 3 mm, glandular hairs often abundant. Leaf blades ovate, broadly ovate, or round, unlobed or 3- or 5-lobed, 3–6 cm, often leathery, surfaces: abaxial sometimes glossy green, adaxial densely tawny-hairy, basal sinus open, not overlapping. Inflorescences interrupted, spicate, flower clusters sessile, glomerate, 10+-flowered; involucellar bractlets awl-shaped to filiform, 5–15 × 1 mm, 2/3–1 1/2 times calyx length. Flowers: calyx angled in bud, 6–14 mm, lobes triangular to ovate, 4–11 × 2.3–3.5(–5) mm, slightly less to slightly more than 2 times as long as wide, equaling to 3 times tube length, apex acute to acuminate, sparsely bristly-hairy, hairs 1–few-armed, to 3 mm; petals pale pink, 1–2 cm. Mericarps 2.4–3.2 mm. 2n = 34.


Phenology: Flowering Mar–Jun(Sep–Oct).
Habitat: Chaparral, coastal sage scrub ecotone
Elevation: (100–)300–1100 m

Distribution

V6 517-distribution-map.jpg

Calif., Mexico (Baja California).

Discussion

Malacothamnus densiflorus occurs in the southern Coast Ranges. Plants with relatively short involucellar bractlets and calyx measurements in the lower range have been recognized as var. viscidus; intergradation with more typical forms is complete. Malacothamnus densiflorus intergrades with M. fasciculatus at lower elevations of the coastal Peninsula Ranges in San Diego County.

Selected References

None.

Lower Taxa

None.
... more about "Malacothamnus densiflorus"
David M. Bates +
(S. Watson) Greene +
Malvastrum densiflorum +
Dense-flowered or yellowstem bushmallow +
Calif. +  and Mexico (Baja California). +
(100–)300–1100 m +
Chaparral, coastal sage scrub ecotone +
Flowering Mar–Jun(Sep–Oct). +
Leafl. Bot. Observ. Crit. +
Malacothamnus densiflorus var. viscidus +, Malvastrum densiflorum var. viscidum +, M. viscidum +, Sphaeralcea densiflora +  and S. densiflora var. viscida +
Malacothamnus densiflorus +
Malacothamnus +
species +