Asclepias involucrata
Asclepias eriocarpa
dwarf milkweed, largeseed milkweed
Indian milkweed, kotolo, woollypod milkweed, wooly-pod or kotolo or Indian milkweed
1–15, decumbent, unbranched or branched near base, 5–18 cm, puberulent with curved trichomes to pilosulous, not glaucous, rhizomatous.
1–10, erect to spreading, rarely branched, 30–100 cm, tomentose to puberulent with curved trichomes or glabrate, not glaucous, rhizomatous.
opposite or subopposite to alternate, petiolate, with 1 or 2 stipular colleters on either side of petiole;
petiole 1–2 mm, pilosulous to glabrate;
blade linear to narrowly lanceolate, 1.5–12 × 0.2–0.8 cm, chartaceous, base cuneate to truncate, margins sometimes crisped, apex acute, mucronate, venation obscure to faintly eucamptodromous, surfaces sparsely pilosulous to glabrate, midvein puberulent with curved trichomes to pilosulous, margins densely ciliate, laminar colleters absent.
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.
terminal, sessile, 6–35-flowered, bracts few.
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.
12–19 mm, puberulent with curved trichomes to pilosulous.
15–50 mm, densely tomentose.
erect to spreading;
calyx lobes elliptic, 2.5–3 mm, apex acute, pilosulous;
corolla green, sometimes tinged pink or red (especially abaxially), lobes reflexed, elliptic, 4.5–6 mm, apex acute, glabrous;
gynostegial column 0.5–1 mm;
fused anthers brown, cylindric, 1.5–2 mm, wings right-triangular, slightly open at tip, apical appendages ovate;
corona segments cream, usually with a pink or red dorsal stripe, subsessile, conduplicate, 3.5–4.5 mm, slightly exceeding style apex, apex truncate with a spreading tip, glabrous, internal appendage falcate, exserted, sharply inflexed towards the style apex, glabrous;
style apex shallowly depressed, cream or greenish cream to pink.
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.
ovate, 7–8 × 5–6 mm, margin thickly winged, faces papillose and rugulose, lepidote;
coma 1.5–2 cm.
ovate, 7–9 × 4–6 mm, margin narrowly winged, faces faintly rugulose;
coma 2.5–3 cm.
erect on upcurved pedicels, ovoid, 4.5–5.5 × 1.5–2 cm, apex acuminate, rugose, faintly striate, minutely puberulent with curved trichomes to pilosulous.
erect on upcurved pedicels, lance-ovoid, 5–10 × 1.5–3 cm, apex apiculate, smooth, densely tomentose.
Asclepias involucrata
Asclepias eriocarpa
Despite the common name dwarf milkweed, Asclepias involucrata is larger than the sympatric A. uncialis, to which it bears a great similarity in the absence of flowers or fruit. In such conditions, A. involucrata is highly cryptic among the short-statured bunch grasses with which it grows. It senesces typically by summer’s end, contributing to the impression that the species is not common. It has occasionally been circumscribed to include A. macrosperma (for example, E. Sundell 1994), although the distinctions made by R. E. Woodson Jr. (1954) were sound. Nonetheless, where the ranges of these largely parapatric species meet, in an arc from northwestern New Mexico to central Arizona, plants of intermediate morphology can be found. It is unknown whether these represent relics of the speciation process or examples of recent hybridization. Asclepias involucrata is rare and of conservation concern in Colorado (Baca, Bent, and Las Animas counties) and Oklahoma (Cimarron County). It is probably extirpated from Kansas (Stevens County), where it is known from a single, historical record. Reports from northern Arizona, southwestern Colorado, and Utah are based on records of A. macrosperma.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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