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hair-spine prickly pear, panhandle prickly pear, plains prickly pear, starvation prickly-pear

plains pricklypear

Habit Shrubs, low, 10–25 cm, with ± prostrate branches. Shrubs, low, to 0.4 m, creeping from clumps, sometimes from thickened rootstocks.
Stem

segments not easily detached, green, elliptic to narrowly to broadly obovate to circular, 4–27 × 2–18 cm, low tuberculate;

areoles 4–14 per diagonal row across midstem segment, subcircular, 3–6 mm;

wool tan to brown.

segments not easily detached, pale green to deep green, graying with age, wrinkled when stressed, flattened, broadly obovate to ovate, 6.5–15 × 4–10 cm, tuberculate, glossy, glabrous;

areoles 6–9 per diagonal row across midstem segment, oval, obovate, or subcircular, 2.5–5 × 1.5–4 mm;

wool tan, aging brown.

Spines

at all or only distal areoles of stem segment, terete to flattened, stout to acicular to bristlelike, straight to curling, of 1 or 2 kinds;

if 1 kind: 0–18 per areole, spreading and curling in various directions, sometimes straight, erect, ascending to deflexed, yellow to dark brown to black, turning gray, pink-gray to gray-brown, longest (35–)40–90(–185) mm;

if ± 2 kinds: major spines (0–)1–5, reflexed to porrect, yellow-brown to brown to gray, longest 20–150 mm;

minor spines (0–)5–11, deflexed, white to white-gray, longest 4–16 mm.

1–9 on most areoles to only on distal 1/2 of stem segment, white to gray with pale brown tips and bases, sometimes brown throughout;

central spines 1–3, all deflexed or 1–2 porrect or ascending, terete or flattened, occasionally spirally twisted, 25–70 mm; small spines (2–)3–6(–8) strongly deflexed, usually slender, even bristlelike, 5–15 mm.

Glochids

inconspicuous, in narrow, tidy crescent at adaxial edge of areole or in broad, brushy crescent and tuft, yellow to reddish, aging brown, to 10 mm.

forming a well developed adaxial tuft, yellow to brownish white, to 6 mm.

Flowers

inner tepals yellow to magenta throughout, 25–40 mm;

filaments white, yellow, or red to magenta (flowers may superficially appear bicolored);

anthers yellow;

style white to pale pink;

stigma lobes green.

inner tepals yellow to gold, commonly darker to red near base, broadly spatulate, 30–40 mm, apiculate;

filaments usually pale yellow;

anthers yellow;

style whitish to pale green;

stigma lobes greenish.

Fruits

tan to brown, ± cylindric, 15–45 × 12–25 mm, dry at maturity, glabrous, sometimes burlike;

areoles 10–33, each or only distal areoles bearing 3–16 spines, 4–20 mm.

purple-red, oval to broadly ovate, subspheric or short ovoid, bases not narrowed, 30 × 20–25 mm, fleshy, base not narrowed, glabrous, spineless or nearly so;

umbilicus deep;

areoles 18–30.

Seeds

tan to gray, flattened, warped, oblong to subcircular, 3–7 × 2–4 mm;

girdle protruding 1–2 mm.

whitish to tan, irregularly shaped, flattened, 4–6 × 3–4 mm;

girdle protruding 1–2 mm.

2n

= 44, 66.

Opuntia polyacantha

Opuntia tortispina

Phenology Flowering spring–early summer (Apr–Jul).
Habitat Grass-lands, pinyon-juniper-oak woodlands, sandy or shaley flats, rocky hills
Elevation 1400-1800 m (4600-5900 ft)
Distribution
from FNA
AZ; CA; CO; ID; KS; MT; ND; NE; NM; NV; OK; SD; TX; UT; WY; AB; SK; n Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; KS; NE; NM; OK; TX; WY
[BONAP county map]
Discussion

Varieties 5 (5 in the flora).

Populations of Opuntia polyacantha with spines few or absent (especially var. hystricina) were the basis for several names including O. juniperina, O. utahensis, and O. rhodantha.

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

Opuntia tortispina is apparently of hybrid origin. It has intermediate character states from its putative parents, O. macrorhiza (fleshy and spineless fruits) and O. polyacantha (areoles with basal deflexed spines and barrel-shaped fruits). The spirally twisted spines, which the specific epithet implies, are not at all characteristic for this species. When O. tortispina and O. cymochila are considered conspecific, the former has priority, as first selected by N. L. Britton and J. N. Rose (1919–1923, vol. 1).

One favored hypothesis as to the origins is that the O. humifusa-O. macrorhiza-O. pottsii complex spread across the United States from the east coast to Arizona. Opuntia polyacantha originated in north-central Mexico and spread northward. Tetraploid O. macrorhiza came into contact with the east flank of O. polyacantha and hybridized (probably repeatedly, even at present), producing the highly variable taxon referred to here as O. tortispina, which then spread eastward onto the plains. Opuntia tortispina has hexaploid members, presumably from unions of reduced and unreduced gametes. Those hexaploids apparently hybridize with hexaploid O. phaeacantha and add further to variation of O. tortispina. Many of these variations have been formally named or since treated as synonyms of O. macrorhiza.

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

Key
1. Areoles 4-6 per diagonal row across midstem segment; stem segments 4-7 × 2-3(-5) cm, elliptic to very narrowly obovate; Texas, New Mexico, Mexico
var. arenaria
1. Areoles 6-14 per diagonal row across midstem segment; stem segments 6-27 × 5-18 cm, obovate to circular or, if elliptic, longer than 9 cm; widespread in w United States and Canada
→ 2
2. Spines of 2 kinds: major spines 1-3 per areole, usually deflexed on terminal stem segment, but sometimes ascending at stem segment apex; minor spines 1-3 per areole, deflexed, white, subtending major spines
→ 3
2. Spines of 1 kind, grading in length, from ascending to deflexed, 7-18 per areole, longest spines of terminal stem segment porrect to ascending, shorter spines deflexed to porrect
→ 4
3. Longest spines 2-4 cm; areoles 6-13 mm apart; stem segments 6-12 cm; Great Plains, n and e Great Basin Desert
var. polyacantha
3. Longest spines 4.5-12 cm; areoles 12-30 mm apart; stem segments 10-27 cm; Arizona and Utah border
var. nicholii
4. Spines usually dark brown, those of proximal stem segments like those of terminal stem segments, porrect to ascending, straight and stiff; fruit areoles 11-21, spiny but not burlike
var. hystricina
4. Spines usually pale, those of proximal stem segments not like those of terminals stem segments, more numerous, longer and more reflexed, straight or flexuous and/or hairlike or threadlike; fruit areoles 20-33, spiny, forming dense bur
var. erinacea
Source FNA vol. 4. FNA vol. 4, p. 132.
Parent taxa Cactaceae > subfam. Opuntioideae > Opuntia Cactaceae > subfam. Opuntioideae > Opuntia
Sibling taxa
O. aciculata, O. atrispina, O. aurea, O. aureispina, O. basilaris, O. chisosensis, O. chlorotica, O. cubensis, O. ellisiana, O. engelmannii, O. ficus-indica, O. fragilis, O. humifusa, O. littoralis, O. macrocentra, O. macrorhiza, O. microdasys, O. oricola, O. phaeacantha, O. pinkavae, O. pottsii, O. pusilla, O. rufida, O. santa-rita, O. stricta, O. strigil, O. tortispina, O. triacantha, O. ×columbiana, O. ×curvispina, O. ×occidentalis, O. ×spinosibacca, O. ×vaseyi
O. aciculata, O. atrispina, O. aurea, O. aureispina, O. basilaris, O. chisosensis, O. chlorotica, O. cubensis, O. ellisiana, O. engelmannii, O. ficus-indica, O. fragilis, O. humifusa, O. littoralis, O. macrocentra, O. macrorhiza, O. microdasys, O. oricola, O. phaeacantha, O. pinkavae, O. polyacantha, O. pottsii, O. pusilla, O. rufida, O. santa-rita, O. stricta, O. strigil, O. triacantha, O. ×columbiana, O. ×curvispina, O. ×occidentalis, O. ×spinosibacca, O. ×vaseyi
Subordinate taxa
O. polyacantha var. arenaria, O. polyacantha var. erinacea, O. polyacantha var. hystricina, O. polyacantha var. nicholii, O. polyacantha var. polyacantha
Synonyms Cactus ferox, Tunas polyacantha O. cymochila, O. mackensenii, O. tortispina var. cymochila
Name authority Haworth: Suppl. Pl. Succ., 82. (1819) Engelmann & J. M. Bigelow: Proc. Amer. Acad. Arts 3: 293. (1856)
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