Opuntia basilaris

Engelmann & J. M. Bigelow

Proc. Amer. Acad. Arts 3: 298. 1856.

Common names: Beavertail pricklypear
Illustrated
Treatment appears in FNA Volume 4. Treatment on page 144. Mentioned on page 143.

Shrubs, forming clumps, 1–2(–3) segments tall, to 7–40 cm. Stem segments not disarticulating, blue- to yellow-green, sometimes tinged maroon-purple, flattened, spatulate to broadly obovate or subcircular, thick, 5–22(–35) × 2–13.5(–16) cm, nearly smooth, papillose to puberulent (rarely glabrous); areoles 4–16(–19) per diagonal row across midstem segment, circular to elliptic, 3–5 × 3 mm; wool white to tan, aging gray. Spines 0(–8) per areole, when present, usually in distal areoles, spreading, yellow, straight, acicular, 5–25 mm. Glochids numerous, nearly filling areoles, yellow to red-brown or dark brown, to 3 mm. Flowers: inner tepals pink to magenta throughout (rarely white), 25–40 mm; filaments red-magenta (rarely pale); anthers yellowish; style white to pink; stigma lobes white to cream. Fruits maturing tan, 20–40 × 15–23 mm, dry at maturity, puberulent, spineless (except in var. treleasei); umbilicus 5–12 mm deep; areoles 24–76. Seeds yellowish to tan, ± subspheric but angular, thick, 6.5–9 × 6.5–7 mm, sides smooth or bearing 1–3 depressions; girdle protruding to 1 mm.

Distribution

V4 274-distribution-map.gif

Ariz., Calif., Nev., Utah, n Mexico.

Discussion

Varieties 4 (4 in the flora).

Selected References

None.

Key

1 Stem segments bearing spines in at least several of distal areoles Opuntia basilaris var. treleasei
1 Stem segments essentially spineless (rarely 1-few per stem segment) > 2
2 Stem segments broadly obovoid to subcircular, erect; areoles (8-)10-16(-19) per diagonal row across midstem segment Opuntia basilaris var. basilaris
2 Stem segments spatulate to elongate, oblong, usually decumbent; areoles 4-8(-9) per diagonal row across midstem segment > 3
3 Stem segments spatulate, apex rounded; areoles 4-8(-9) per diagonal row across midstem segment; Arizona, Utah. Opuntia basilaris var. longiareolata
3 Stem segments oblong to narrowly spatulate to subcylindric, apex truncate to rounded; areoles 4-6(-7) per diagonal row across midstem segment; California Opuntia basilaris var. brachyclad