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big-leaf milkweed, Lemmon's milkweed

Curtiss' milkweed

Habit Herbs. Herbs.
Stems

1–3, erect to ascending, unbranched, very stout, 100–150 cm, densely hirsute, not glaucous, rhizomes absent(?).

1, erect, often purplish, sometimes branched in inflorescence, 15–100 cm, puberulent with curved trichomes, not glaucous, rhizomes absent.

Leaves

opposite, petiolate, with 1 stipular colleter on each side of petiole;

petiole 1–5 mm, hirsute;

blade oval or oblong to ovate, 7–22 × 3–14 cm, subsucculent, base truncate to subcordate, margins entire, apex obtuse to truncate or emarginate, mucronate, venation brochidodromous, secondary veins nearly orthogonal, surfaces hirsute, margins ciliate, 8–16 laminar colleters.

opposite, petiolate, with 1 or 2 stipular colleters on each side of petiole;

petiole 4–7 mm, puberulent with curved trichomes;

blade oblong, elliptic, or oval to obovate, oblanceolate, ovate, or lanceolate, 1.8–5 × 0.5–2.5 cm, chartaceous, base obtuse to cuneate or rounded, margins entire, apex truncate to emarginate or acute, mucronate, venation brochidodromous to eucamptodromous, surfaces sparsely puberulent on midvein with curved trichomes, margins inconspicuously ciliate to glabrate, 2–6 laminar colleters.

Inflorescences

terminal, paired, and extra-axillary, pedunculate, 21–53-flowered;

peduncle 6–13 cm, densely hirsute, with 1 caducous bract at the base of each pedicel.

terminal and extra-axillary at upper nodes, sessile or pedunculate, 15–45-flowered;

peduncle 0–4 cm, puberulent on 1 side with curved trichomes, with 1 caducous bract at the base of each pedicel.

Pedicels

13–22 mm, densely hirsute.

10–14 mm, sparsely puberulent with curved trichomes.

Flowers

erect to pendent;

calyx lobes lanceolate, 3.5–6 mm, apex acute, hirsute;

corolla cream to greenish cream or ochroleucous, sometimes tinged pink, lobes reflexed with spreading tips, elliptic, 9–11 mm, apex acute, glabrous;

gynostegial column 0.5–1 mm;

fused anthers greenish brown, cylindric, 2.5–3 mm, wings right-triangular, closed, apical appendages oval;

corona segments cream to ochroleucous, sometimes tinged pink, shiny, subsessile, conduplicate, 6–8 mm, equaling or exceeding style apex, apex truncate, spreading and tapering, glabrous, internal appendage laterally compressed, erect, barely exserted, glabrous;

style apex shallowly depressed, green or pink.

erect;

calyx lobes lanceolate, 2–3 mm, apex acute, glabrous;

corolla green with bronze or purplish tinge, lobes reflexed with spreading tips, elliptic, 4–5 mm, apex acute, glabrous;

gynostegial column 0.5–1 mm;

fused anthers green, obconic, 1–1.5 mm, wings broadly triangular, widest at middle, closed, apical appendages ovate;

corona segments white with a green and/or purple dorsal midline, sessile, conduplicate and dorsally flattened, 5–6 mm, greatly exceeding style apex, apex attenuate, glabrous, internal appendage falcate, exserted, sharply inflexed over style apex, glabrous;

style apex shallowly depressed, green to cream.

Seeds

ovate, 6–7 × 4–5 mm, margin winged, faces minutely rugulose;

coma 4–4.5 cm.

ovate, 8–9 × 5–6 mm, margin winged, erose, faces sparsely papillose;

coma 3.5–4 cm.

Follicles

erect on upcurved pedicels, lance-ovoid, 9.5–13.5 × 2–3 cm, apex attenuate, smooth, densely hirsute.

erect on upcurved pedicels, fusiform, 8–10.5 × 0.8–1.5 cm, apex long-acuminate, smooth, puberulent with curved trichomes.

Asclepias lemmonii

Asclepias curtissii

Phenology Flowering Jun–Sep; fruiting Aug–Oct. Flowering Apr–Oct; fruiting Jul–Oct.
Habitat Canyons, slopes, streamsides, rocky and clay soils, pine-oak, pine, and riparian forests, oak woodlands, marshes. Low ridges, sandy soils, oak-palmetto sand scrub, pinelands.
Elevation 1200–2200 m. (3900–7200 ft.) 0–50 m. (0–200 ft.)
Distribution
from FNA
AZ; Mexico (Chihuahua, Durango, Jalisco, Sonora, Zacatecas)
[WildflowerSearch map]
[BONAP county map]
from FNA
FL
[WildflowerSearch map]
[BONAP county map]
Discussion

A highly distinctive species, Asclepias lemmonii just barely enters the United States in southern Arizona (Cochise, Pima, and Santa Cruz counties), where it inhabits canyons in pine-oak clad sky-island ranges. Asclepias elata is a common co-inhabitant of these canyons. Asclepias lemmonii has been documented from the Baboquiviri, Chiricahua, Huachuca, and Santa Rita mountains, and it is not common in any of these. It is considered to be of conservation concern in Arizona. The large, hirsute leaves with nearly orthogonal venation and robust, hirsute stems of A. lemmonii are unmatched among American milkweeds. Plants may reach heights over 2 m in the main range of the species in the northern Sierra Madre Occidental.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Asclepias curtissii is endemic to white-sand substrates at interior and coastal sites on the Florida peninsula. Although the species is not considered to face imminent threat of extirpation, the scrub habitats in which it is found have been, and continue to be, heavily impacted by development. Asclepias curtissii cannot be mistaken for any other milkweed in its range when in flower; however, it occurs in the same habitats as A. tomentosa, and these species overlap considerably in vegetative features. The leaves of A. curtissii can be distinguished from those of A. tomentosa by trichomes limited to the midvein (versus sparsely to densely puberulent or tomentulose throughout).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 14. FNA vol. 14.
Parent taxa Apocynaceae > Asclepias Apocynaceae > Asclepias
Sibling taxa
A. albicans, A. amplexicaulis, A. angustifolia, A. arenaria, A. asperula, A. brachystephana, A. californica, A. cinerea, A. connivens, A. cordifolia, A. cryptoceras, A. curassavica, A. curtissii, A. cutleri, A. eastwoodiana, A. elata, A. emoryi, A. engelmanniana, A. eriocarpa, A. erosa, A. exaltata, A. fascicularis, A. feayi, A. hallii, A. hirtella, A. humistrata, A. hypoleuca, A. incarnata, A. involucrata, A. labriformis, A. lanceolata, A. lanuginosa, A. latifolia, A. linaria, A. linearis, A. longifolia, A. macrosperma, A. macrotis, A. meadii, A. michauxii, A. nummularia, A. nyctaginifolia, A. obovata, A. oenotheroides, A. ovalifolia, A. pedicellata, A. perennis, A. prostrata, A. pumila, A. purpurascens, A. quadrifolia, A. quinquedentata, A. rubra, A. rusbyi, A. ruthiae, A. sanjuanensis, A. scaposa, A. solanoana, A. speciosa, A. sperryi, A. stenophylla, A. subulata, A. subverticillata, A. sullivantii, A. syriaca, A. texana, A. tomentosa, A. tuberosa, A. uncialis, A. variegata, A. verticillata, A. vestita, A. viridiflora, A. viridis, A. viridula, A. welshii
A. albicans, A. amplexicaulis, A. angustifolia, A. arenaria, A. asperula, A. brachystephana, A. californica, A. cinerea, A. connivens, A. cordifolia, A. cryptoceras, A. curassavica, A. cutleri, A. eastwoodiana, A. elata, A. emoryi, A. engelmanniana, A. eriocarpa, A. erosa, A. exaltata, A. fascicularis, A. feayi, A. hallii, A. hirtella, A. humistrata, A. hypoleuca, A. incarnata, A. involucrata, A. labriformis, A. lanceolata, A. lanuginosa, A. latifolia, A. lemmonii, A. linaria, A. linearis, A. longifolia, A. macrosperma, A. macrotis, A. meadii, A. michauxii, A. nummularia, A. nyctaginifolia, A. obovata, A. oenotheroides, A. ovalifolia, A. pedicellata, A. perennis, A. prostrata, A. pumila, A. purpurascens, A. quadrifolia, A. quinquedentata, A. rubra, A. rusbyi, A. ruthiae, A. sanjuanensis, A. scaposa, A. solanoana, A. speciosa, A. sperryi, A. stenophylla, A. subulata, A. subverticillata, A. sullivantii, A. syriaca, A. texana, A. tomentosa, A. tuberosa, A. uncialis, A. variegata, A. verticillata, A. vestita, A. viridiflora, A. viridis, A. viridula, A. welshii
Synonyms Oxypteryx curtissii
Name authority A. Gray: Proc. Amer. Acad. Arts 19: 85. (1883) — (as lemmoni) A. Gray: Proc. Amer. Acad. Arts 19: 85. (1883)
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