Asclepias lanceolata

Herbs. Stems 1, erect, unbranched, 60–125 cm, gla­brous, not glaucous, rhizomes absent. Leaves opposite, sessile or petiolate, with 1 stipular colleter on each side of petiole on a ciliate interpetiolar ridge; petiole 0–1 mm, ciliate; blade linear to linear-lanceolate, somewhat conduplicate, 7–25 × 0.2–1.7 cm, chartaceous, base cuneate, margins entire, apex attenuate, mucronate, venation faintly brochidodromous to obscure, surfaces glabrous, margins inconspicuously ciliate, 8–12 laminar colleters, usually obscured by conduplicate petiole. Inflorescences terminal and often extra-axillary at an upper node, usually branched, pedunculate, 4–16-flowered; peduncle 1–7.5 cm, puberulent on 1 side with curved trichomes, with 1 caducous bract at the base of each pedicel. Pedicels 13–19 mm, puberulent on 1 side with curved trichomes. Flowers erect; calyx lobes narrowly lanceolate, 2–3 mm, apex acute, puberulent with curved trichomes to glabrate; corolla red, lobes reflexed, usually with spreading tips, elliptic, 9–10 mm, apex acute, glabrous abaxially, minutely papillose at base adaxially; gynostegial column 1.5–2 mm; fused anthers green, tinged yellow to red, truncately obconic, 2.5 mm, wings narrowly right-triangular, slightly open at base, apical appendages deltoid; corona segments yellow to reddish orange, stipitate, broadly tubular, dorsally flattened, 5–6 mm, exceeding style apex, apex obtuse, flared, glabrous, internal appendage subulate, exserted, sharply inflexed over style apex, glabrous; style apex shallowly depressed, red. Follicles erect on upcurved pedicels, narrowly fusiform, 5.5–10 × 0.8–1 cm, apex attenuate to long-acuminate, smooth, sparsely pilosulous or puberulent with curved trichomes to glabrate. Seeds broadly oval, 8–10 × 6–8 mm, margin winged, faces smooth; coma 3–3.5 cm.

Phenology: Flowering year-round; fruiting Jun–Nov.
Habitat: Saltwater and freshwater marshes, pond edges, streamsides, bogs, swamps, ditches, glades, depressions, hill slopes, satu­rated sandy and silty soils, pine flatwoods, pine-oak forests, savannas, meadows, and barrens, thickets.
Elevation: 0–100 m.

Distribution

• Generated Map
• Legacy Map

Ala., Del., Fla., Ga., La., Md., Miss., N.J., N.C., S.C., Tex., Va.

Discussion

Asclepias lanceolata is a characteristic wetland milk­weed of the Atlantic and Gulf coastal plains, where it occurs sometimes with its similar relative, A. rubra. It is distinguished from A. rubra by flower color (shades of orange, yellow, and red versus pink, lavender, and reddish purple), corona segment apex (obtuse versus acute), and leaf shape (linear to linear-lanceolate versus narrowly lanceolate to ovate). These species are known to hybridize locally, particularly in North Carolina, and putative hybrids can be recognized by intermediate floral and vegetative traits. The pattern of yellow-orange coronas paired with red corollas is similar to that of the introduced A. curassavica, and these species are some­times confused. Asclepias curassavica differs by usually pure yellow (versus orangish) coronas, more flowers per umbel, much shorter peduncles, and wider, shorter leaf blades. Asclepias lanceolata sometimes is confused also with orange-flowered A. tuberosa, although that species only rarely has bicolored flowers, and the two are quite distinct in habitat, growth form, and vestiture. Through habitat loss, A. lanceolata has become quite rare in some areas, particularly the north­eastern United States. It is considered to be of conservation concern in Delaware (Sussex County), Maryland (Dorchester County), and New Jersey. It has been reported, but not documented, from Tennessee, and its occurrence there seems unlikely. The report may be based on confusion with the name of the formerly recognized (and unrelated) A. viridiflora var. lanceolata.

Selected References

None.

Lower Taxa

None.