Asclepias cordifolia |
Asclepias connivens |
|
---|---|---|
heart-leaf milkweed, purple milkweed |
large-flower milkweed |
|
Habit | Herbs. | Herbs. |
Stems | 1–20, ascending to spreading, unbranched, 25–100 cm, glabrous, glaucous, rhizomes absent. |
1, erect, unbranched (rarely branched), 25–90 cm, minutely puberulent with curved trichomes or pilose to glabrate, not glaucous, rhizomes absent. |
Leaves | 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, with 1 or 2 stipular colleters on each side of petiole; petiole 0–1 mm, puberulent with curved trichomes to glabrate; blade narrowly elliptic to linear or oblanceolate, 2.5–8 × 0.3–2.5 cm, chartaceous, base cuneate, margins entire, apex acute to rounded, mucronate, venation brochidodromous, surfaces sparsely pilose to glabrate, midvein puberulent with curved trichomes to glabrate, margins ciliate, 0–6 laminar colleters. |
Inflorescences | 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, pedunculate, 4–8-flowered; peduncle 0.9–6 cm, densely puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel. |
Pedicels | 16–37 mm, sparsely pilose. |
10–20 mm, densely puberulent with curved trichomes. |
Flowers | 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 lanceolate, 4–6 mm, apex acute, sparsely pilosulous; corollas green, sometimes tinged brown at apex, lobes reflexed with spreading tips, elliptic, 10–13 mm, apex acute to obtuse, sometimes emarginate, glabrous; gynostegial column 1–1.5 mm; fused anthers green, obconic, 3–3.5 mm, wings narrowly right-triangular, distended at base, closed, apical appendages oval; corona segments cream to pale green, stipitate, clavate, incurved, 8–10 mm, greatly exceeding style apex, apex rounded, glabrous, internal appendage a hidden crest, glabrous, apices of the 5 segments sometimes connivent; style apex depressed, green. |
Seeds | ovate, 8–9 × 5–7 mm, margin not winged, faces reticulate-rugulose; coma 3–3.5 cm. |
ovate, 7–9 × 5–6 mm, margin winged, faces minutely and sparsely rugulose; coma 3–3.5 cm. |
Follicles | 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, fusiform, 11.5–15 × 0.5–1.4 cm, apex long-attenuate, smooth, minutely pilosulous. |
2n | = 22. |
|
Asclepias cordifolia |
Asclepias connivens |
|
Phenology | Flowering Mar–Jul(–Aug); fruiting Jun–Sep. | Flowering May–Aug(–Sep); fruiting Jul–Sep(–Nov). |
Habitat | Hillsides, canyons, ridge tops, streamsides, seeps, basalt, serpentine, gabbro, granite, shale, limestone, talus slopes, gravel, alluvium, oak woodlands, mixed evergreen, douglas-fir, pine, pine-oak, and riparian forests, chaparral, timberline meadows, grasslands. | Flats, sandy soils, pine flatwoods and barrens, often recently burned, wet meadows, marshes, bogs, swamps. |
Elevation | 50–2200(–2800) m. [160–7200(–9200) ft.] | 0–200 m. [0–700 ft.] |
Distribution |
CA; NV; OR
|
AL; FL; GA; SC
|
Discussion | 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 connivens is a singular species—the large, incurved, clavate corona segments are unlike any others in the genus. With wide leaves and large flowers, A. connivens is more conspicuous than most co-occurring milkweeds, such as A. cinerea, A. feayi, A. pedicellata, and A. viridula. It prefers wet soils and often occurs at the same sites as A. viridula and the red-orange-flowered A. lanceolata. Asclepias connivens barely enters South Carolina in Jasper and Beaufort counties and is considered rare and to be of conservation concern in that state. It has been reported from Mississippi, but there are no specimens from that state, and occurrence there seems unlikely, as A. connivens has not been documented from southwestern Alabama either. It would be interesting to discover what pollinates the large and unusual flower of A. connivens; however, there appear to be no reports of flower visitors to this species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 14. | FNA vol. 14. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Acerates cordifolia, Gomphocarpus cordifolius | Anantherix connivens |
Name authority | (Bentham) Jepson: Fl. W. Calif., 384. (1901) | Baldwin in Elliott: Sketch Bot. S. Carolina 1: 320. (1817) |
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