Asclepias longifolia
Asclepias lanceolata
Florida milkweed, long-leaf milkweed
few-flower milkweed, smooth-orange milkweed
1–few, spreading to decumbent, unbranched, 25–70 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.
1, erect, unbranched, 60–125 cm, glabrous, not glaucous, rhizomes absent.
opposite or alternate, sessile or petiolate, with 1 or 2 stipular colleters on each side of petiole, also in axil;
petiole 0–2 mm, puberulent with curved trichomes;
blade linear to linear-lanceolate, 5–18 × 0.2–1 cm, chartaceous, base cuneate, margins entire, apex acute to attenuate, sometimes mucronate, venation brochidodromous, surfaces scabridulous to puberulent with curved trichomes, especially on veins, margins ciliate, laminar colleters absent.
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.
terminal and extra-axillary at upper nodes, sessile or pedunculate, 13–28(–36)-flowered;
peduncle 0–6 cm, puberulent with curved trichomes, with 1 caducous bract at the base of each pedicel.
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.
9–16 mm, puberulent with curved trichomes.
13–19 mm, puberulent on 1 side with curved trichomes.
erect to spreading;
calyx lobes narrowly lanceolate, 1.5–2 mm, apex acute, puberulent with curved trichomes;
corolla white to greenish cream, purple at lobe tips, lobes reflexed, oblong, 3–5 mm, apex obtuse, glabrous;
gynostegial column 0.2–0.5 mm;
fused anthers green or brown, cylindric, 1–1.5 mm, wings triangular to trapezoidal, widest at middle, slightly open at tip, apical appendages ovate;
corona segments pinkish lavender to red-violet, often with white apex, often a darker red-violet stripe or at base, sessile, laminar, strongly dorsally compressed, margins incurved, appressed to column, curved to subsaccate, 2–2.5 mm, exceeding point of anther wings, greatly exceeded by style apex, apex obtuse to truncate, glabrous, internal appendage absent or obscure, glabrous;
style apex shallowly depressed, greenish cream to green.
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.
ovate, 11–12 × 7–8 mm, margin winged, faces smooth;
coma 4–5 cm.
broadly oval, 8–10 × 6–8 mm, margin winged, faces smooth;
coma 3–3.5 cm.
erect on upcurved pedicels, narrowly fusiform, 8–13.5 × 0.7–1.2 cm, apex attenuate, smooth, puberulent with curved trichomes.
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.
Asclepias longifolia
Asclepias lanceolata
Asclepias longifolia has sometimes been treated to include A. hirtella as conspecific, as discussed under that species. As circumscribed here, the distribution of A. longifolia extends along the Atlantic Coastal Plain south of Delaware to Florida and westward to the Mississppi River. Reports of A. longifolia from west of the Mississippi River in Louisiana and in Texas are assigned here to A. hirtella. Hence, the range of A. longifolia in Louisiana is extremely limited, and the conservation status of this species warrants assessment in that state (Livingston, Saint Helena, Saint Tammany, Tangipahoa, and Washington parishes). Reports of A. longifolia from Maryland and West Virginia have not been confirmed, and the species is considered extirpated from Delaware. Otherwise, it is rare at the northern extent of its range and considered to be of conservation concern in North Carolina and Virginia (Greensville and Prince George counties).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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