1.
Opuntia pusilla
(Haworth) Haworth, Syn. Pl. Succ. 195. 1812.
Sandbur pricklypear
Cactus pusillus
Haworth, Misc. Nat., 188. 1803;
Opuntia drummondii
Graham;
O. tracyi
Britton
Shrubs,
creeping, often forming mats, trailing, to 0.1 m.
Stem segments
easily detached, green, purplish red under stress, flattened, elliptic to linear, sometimes subcylindric (to subspheric), 2.5-5(-8) × 1.2-2.5 cm, tuberculate, glabrous; areoles 2-5 per diagonal row across midstem segment, subcircular, 2-3 mm diam.; wool tan to gray.
Spines
(0-)1-2(-4) per areole, in distal
3
/4 of stem segment areoles (to nearly spineless), porrect to spreading, red-brown, aging gray, stout, straight, terete, to 30 mm, strongly barbed.
Glochids
in crescent at adaxial edge of areole, pale yellow, aging brown, to 3 mm, longest at areole apex.
Flowers:
inner tepals yellow throughout, 20-30 mm; filaments and anthers yellow; style and stigma lobes white.
Fruits
green becoming red-purple at late maturity, barrel-shaped, 18-30 × 12-20 mm, fleshy, glabrous, spineless; areoles 8-16.
Seeds
tan, subcircular, flattened, 4-6 mm diam.; girdle slightly protruding.
2
n
= 44.
Flowering spring (Apr-May). Dune and pine scrub, primarily coastal, sandy openings, dunes, or rocky outcrops; 0-100 m; Ala., Fla., Ga. , Miss., N.C., S.C., Tex.
