Asclepias eriocarpa

Herbs. Stems 1–10, erect to spreading, rarely branched, 30–100 cm, tomentose to puber­ulent with curved trichomes or glabrate, not glaucous, rhizo­matous. Leaves opposite, or alternate or whorled at upper nodes, petiolate, with 0–2 stipular colleters on each side of petiole (sometimes additionally in the axil); petiole 4–15 mm, tomentose; blade oblong or oval to lanceolate or ovate, often conduplicate, 8–20 × 2–8 cm, chartaceous, base obtuse or truncate to cordate, margins entire or often undulate, apex acuminate to obtuse, mucronate, venation brochidodromous, surfaces tomentose to densely puberulent with curved trichomes, margins ciliate, 6–8 laminar colleters. Inflorescences terminal, sometimes branched, and extra-axillary at upper nodes, pedunculate, 12–57-flowered; peduncle 1–10 cm, densely tomentose, with 1 caducous bract at the base of each pedicel. Pedicels 15–50 mm, densely tomentose. Flowers erect to spreading; calyx lobes lanceolate, 3–4 mm, apex acute, densely tomentose; corolla greenish cream, ochroleucous, or pinkish cream, deep pink or tan abaxially, lobes reflexed, tips usually spreading, oval, 7–9 mm, apex acute, tomentose abaxially towards tips, glabrous adaxially; gynostegial column 1–1.5 mm; fused anthers dark brown, cylindric, 2.5–3 mm, wings right-triangular, closed, apical appendages ovate; corona segments cream to dark pink, stipitate, conduplicate, dorsally rounded, 2.5–3 mm, exceeded by style apex, apex truncate, oblique, papillose, internal appendage falcate, exserted, sharply inflexed towards style apex, papillose; style apex shallowly depressed, cream. Follicles erect on upcurved pedicels, lance-ovoid, 5–10 × 1.5–3 cm, apex apiculate, smooth, densely tomentose. Seeds ovate, 7–9 × 4–6 mm, margin narrowly winged, faces faintly rugulose; coma 2.5–3 cm.

Phenology: Flowering (Apr–)May–Oct; fruiting (May–)Jun–Oct.
Habitat: Hills, slopes, ridge tops, flats, valleys, canyons, arroyos, stream banks, granite, rocky, alluvial, clay, and sandy soils, meadows, native and non-native grasslands, cha­parral, coastal sage scrub, oak and pine-oak wood­lands, pine, mixed conifer, and riparian forests, often following fires.
Elevation: 50–2500 m.

Distribution

• Generated Map
• Legacy Map

Calif., Mexico (Baja California).

Discussion

Asclepias eriocarpa is found almost throughout the California Floristic Province in relatively dry, open sites in a variety of vegetation types. It is the only milkweed in the flora area that regularly produces alternate, oppo­site, and whorled leaves on a single stem. Its distribu­tion overlaps that of several other broad-leaved, densely vestitured Asclepias species: A. erosa in desert scrub and dry grasslands, A. californica and A. vestita in chaparral and woodlands, and A. speciosa in woodlands. Com­par­ison to A. erosa is presented under that species. Asclepias eriocarpa is easily distinguished from A. californica by the distinctive red-violet, rounded corona segments that lack appendages in the latter species. Asclepias eriocarpa has corona segments with truncate apices and corolla lobes that are tomentose abaxially only at the apex, in contrast to the obtuse corona segments and uniformly pubescent corolla lobes of A. vestita. Asclepias speciosa has distinctive corona segments with long, tapering apices that are much larger than and are easily distinguished from those of A. eriocarpa. It is possible that A. eriocarpa and A. speciosa occasionally hybridize—R. E. Woodson Jr. speculated (via annotation of the holotype, E. Gifford s.n. [CAS]) that A. giffordii Eastwood represented such a hybrid. That interpretation is accepted here. Asclepias eriocarpa is reported to be a resource for fiber and medicine by Native Americans.

Selected References

None.

Lower Taxa

None.