Asclepias cordifolia
Asclepias nummularia
heart-leaf milkweed, purple milkweed
tuft milkweed
1–20, ascending to spreading, unbranched, 25–100 cm, glabrous, glaucous, rhizomes absent.
1–5, erect, unbranched, 6–15 cm, taller on vegetative or post-reproductive plants, densely tomentose to glabrate, 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, petiolate, with 1 stipular colleter on either side of petiole;
petiole 3–4 mm, tomentose to glabrate;
blade orbiculate to obovate or oblate, 1.5–3.2 × 1.7–4 cm, much larger on vegetative or post-reproductive stems, subsucculent, base rounded to cordate, margins entire, apex truncate or emarginate to rounded or obtuse, venation eucamptodromous, surfaces tomentose to glabrate, laminar colleters 0–10.
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 also extra-axillary, pedunculate, 5–28-flowered;
peduncle 2.7–6 cm, tomentose, with 1 bract at the base of each pedicel.
16–37 mm, sparsely pilose.
12–20 mm, densely pilosulous to tomentulose.
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.
erect;
calyx lobes ovate to lanceolate, 1.5–2.5 mm, apex acute, pilose to tomentulose;
corolla pinkish violet to tan, striate, lobes reflexed, oval, 4–5 mm, apex acute, glabrous abaxially, minutely papillate at base adaxially;
gynostegial column 0.2–0.5 mm;
fused anthers brown, cylindric, 1–1.5 mm, wings curved, closed, apical appendages ovate, erose;
corona segments white apically, red-violet basally, sessile, conduplicate, dorsally rounded, 2.5–3 mm, equaling or exceeding style apex, apex truncate, glabrous, internal appendage falcate, exserted, sharply inflexed over style apex, glabrous;
style apex shallowly depressed, cream to pink.
ovate, 8–9 × 5–7 mm, margin not winged, faces reticulate-rugulose;
coma 3–3.5 cm.
broadly ovate, 6–7 × 4–5 mm, margin winged, corky, erose at chalazal end, faces papillose-rugulose, hirtellous;
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.
erect on upcurved pedicels, lance-ovoid, 4–7.5 × 1.2–1.5 cm, apex long-acuminate, smooth, tomentose.
= 22.
Asclepias cordifolia
Asclepias nummularia
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.)
Asclepias nummularia is the only milkweed in the flora area with small stature and obovate to orbiculate leaves that are bluish under dense tomentum until late in the season. The plants often bear an uncanny resemblance to tiny cabbages. Fruit set may fail across broad regions in some years, perhaps due to drought, although the adequacy of pollination in this species has not been studied. Unlike many species of Asclepias, post-reproductive and non-reproductive plants of A. nummularia often persist until frost. Coupled with the early flowering of this species, vegetative plants are observed and collected far more often than reproductive ones. Some plants persisting into the fall months have much larger leaves and longer stems, especially in shady or moist habitats; these have often been mistaken for A. latifolia, the range of which only barely overlaps that of A. nummularia in Grant County, New Mexico. Asclepias nummularia is not common in New Mexico, where it has been found in Grant, Hidalgo, and Sierra counties, and is only locally common in Texas in the Davis Mountains (Jeff Davis County), and additionally in Brewster and Presidio counties. Populations from San Luis Potosí and south with narrower leaves have been segregated as A. nummularioides W. D. Stevens; recognition of this taxon requires further evaluation.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
