Asclepias cordifolia
Asclepias californica
heart-leaf milkweed, purple milkweed
California milkweed, round-hood milkweed
1–20, ascending to spreading, unbranched, 25–100 cm, glabrous, glaucous, rhizomes absent.
1–20+, decumbent to erect, rarely branched, 15–90 cm, densely tomentose, not glaucous, rhizomes absent.
opposite, sessile, stipular colleters absent;
blade ovate to lanceolate, 3.5–11 × 1.8–8 cm, chartaceous, base cordate, clasping, margins entire, apex acute, mucronate, venation brochidodromous to eucamptodromous, surfaces glabrous, glaucous, margins minutely ciliate, laminar colleters absent.
opposite, sessile or petiolate, stipular colleters absent;
petiole 0–17 mm, densely tomentose;
blade ovate to lanceolate or oval, 5–18 × 2.5–10.5 cm, chartaceous, base cordate to truncate, margins often minutely erose, apex acuminate, venation eucamptodromous to faintly brochidodromous, surfaces densely tomentose to glabrate, margins ciliate, laminar colleters absent.
terminal, branched, sometimes also extra-axillary at upper nodes, pedunculate, 5–20-flowered;
peduncle 0.3–6.5 cm, apically sparsely pilose to glabrate, with few bracts.
terminal, sometimes branched, and extra-axillary at upper nodes, sessile or pedunculate, 5–21-flowered;
peduncle 0–2.5 cm, densely tomentose, with 1 caducous bract at the base of each pedicel.
16–37 mm, sparsely pilose.
15–40 mm, densely tomentose.
erect to pendent;
calyx lobes elliptic to lanceolate, 3–5 mm, apex acute, pilose;
corolla red-violet, lobes reflexed with spreading tips, oval, 6–7 mm, apex acute, glabrous;
gynostegial column 1–1.5 mm;
fused anthers brown, cylindric, 1.5–2 mm, wings right-triangular, open at tip, apical appendages deltoid;
corona segments white, tinged pink to red-violet at base, sessile, tubular, 2–3 mm, exceeded by style apex, base saccate, apex truncate, oblique, glabrous, internal appendage absent;
style apex shallowly depressed, pink to red-violet.
spreading to pendent;
calyx lobes linear to narrowly lanceolate, 4–6 mm, apex acute, densely tomentose;
corolla green or tan (sometimes tinged pink) to pinkish purple, red-violet at base, lobes reflexed with spreading tips, oval, 8–11 mm, apex acute, densely tomentose abaxially, pilose at base adaxially;
gynostegial column 2–3.5 mm;
fused anthers dark brown, columnar, 2–2.5 mm, wings right-triangular, closed, apical appendages deltoid;
corona segments red-violet, sometimes pale at apex, sessile, conduplicate, dorsally rounded, 3–6 mm, exceeded by style apex, base slightly to strongly saccate, margins connivent, apex rounded to truncate, slightly to strongly oblique, papillose, internal appendage absent;
style apex planar, green.
ovate, 8–9 × 5–7 mm, margin not winged, faces reticulate-rugulose;
coma 3–3.5 cm.
broadly oval to orbiculate, 9–12 × 8–11 mm, margin very narrowly winged, faces rugulose;
coma 1.5–2.5 cm.
erect on upcurved pedicels, lance-ovoid, 7.5–10.5 × 1.5–1.8 cm, apex long-acuminate, smooth, glabrous, glaucous.
sometimes paired, erect on upcurved pedicels, ovoid, 5–12.5 × 2–3 cm, apex apiculate to acuminate, longitudinally ridged, densely tomentose.
= 22.
Asclepias cordifolia
Asclepias californica
Fresh leaves and stems of Asclepias cordifolia are often slightly or strongly colored bluish, grayish, or purplish. This is one of the few American species of Asclepias with cavitate corona segments that lack adaxial appendages. Such species were segregated along with diverse African species in Gomphocarpus R. Brown, a polyphyletic segregate (M. Fishbein et al. 2011; D. Chuba et al. 2017). Asclepias cordifolia is a distinctive species unlike any other within its range. It is phylogenetically and geographically isolated, although not highly derived morphologically. In Nevada, A. cordifolia is restricted to the Sierra Nevada, in Carson City, Douglas, and Washoe counties. Its range extends to northern California and southwestern Oregon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Subspecies 2 (2 in the flora).
Asclepias californica is one of the showiest milkweed species in the flora, with red-violet flowers set off by the dense, white, wooly vestiture of the rest of the plant. It is available from California nurseries but can be difficult to maintain in cultivation. An old report of the species from Baja California Sur cannot be confirmed and likely stems from a misidentification or erroneous location. Although the coronas are notoriously variable within the recognized subspecies, the key characters reliably distinguish northern and southern population systems. However, intermediates can be found in the contact zone, in Kern County.
Gomphocarpus tomentosus (Torrey) A. Gray (not Burchell 1822) is an illegitimate name found in some older regional floras that pertains here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Corona segments 4–6 mm, apex usually rounded, opening extending from apex to base more than halfway, often more than three-quarters. | subsp. californica |
1. Corona segments 3–4 mm, apex truncate or rounded, opening extending from apex to base less than, rarely up to, halfway. | subsp. greenei |
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
