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Published In: Medical Flora 2: 247. 1830. (Med. Fl.) Name publication detailView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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1. Opuntia humifusa (Raf.) Raf. (eastern prickly pear)

O. compressa (Salisb.) J.F. Macbr.

Pl. 329 f–c; Map 1400

Plants prostrate or less commonly forming low mounds, the main roots sometimes tuberous-thickened. Pads 4–8(–12) cm long, obovate to nearly circular, dark or bright green, often somewhat shiny at maturity, often somewhat glaucous when young. Areoles mostly 10–30 mm apart, 2–4 mm in diameter, oval to circular. Glochids 2–3 mm long, yellowish brown to orangish brown. Spines absent or 1(–3) per areole, often restricted to near the margin of the pads, 1–5 cm long, spreading or deflexed, straight, not flattened, white to gray or brown, often purplish toward the base. Tepals to 3 cm long, the petaloid ones yellow, sometimes orange or pinkish-tinged toward the base. Stigma lobes white or pale yellow. Fruits 2–5 cm long, the surface with glochids but no spines, the areoles sometimes restricted to the apical rim, remaining fleshy with age, green, sometimes becoming reddish- or purplish-tinged with age. Seeds 3.5–4.5 mm long, the raised rim relatively short (extending about 0.5 mm beyond the seed body) and smooth. 2n=22, 44. May–July.

Scattered nearly throughout the state (eastern U.S. west to South Dakota and New Mexico, disjunct in Montana; Mexico). Rocky areas of upland prairies, sand prairies, glades, tops and exposed ledges of bluffs, and rocky stream terraces; also pastures, roadsides, railroads, and open, disturbed areas.

Benson (1982) treated O. humifusa as comprising three varieties, the widespread var. humifusa and the southeastern Coastal Plain endemics var. ammophila (Small) L.D. Benson and var. austrina (Small) Dress. Many subsequent authors have rejected the last two as mere morphological variants within the species that tend to differ in their more upright growth form and longer, narrower pads. These taxa require further study. For a discussion of difficulties in separating O. humifusa from O. macrorhiza, see the treatment of that species.

 


 

 
 
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