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

Photo is of parent taxon

Navajo Bridge pricklypear

Habit Shrubs, low, 10–25 cm, with ± prostrate branches.
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 narrowly to broadly obovate, 10–27 × 7–18 cm;

areoles 8–11 per diagonal row across midstem segment, 12–30 mm apart.

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.

in most areoles, of 2 kinds: major spines 1–5 per areole, down curved, ascending near stem segment apex, pink-gray or basal 2/3 brown to black, the longest 45–150 mm;

minor spines 3–8 per areole, deflexed, white to gray, 60–220 cm (spine clusters easily detached in preparing specimens).

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.

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.

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.

stout;

areoles 18–24, most bearing 3–12 spines, 8–17 mm.

Seeds

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

girdle protruding 1–2 mm.

2n

= 66.

Opuntia polyacantha

Opuntia polyacantha var. nicholii

Phenology Flowering spring.
Habitat Barren areas with saltbush and ephedra, limestone or red, sandy soils
Elevation 1200-1300 m (3900-4300 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
AZ; UT
[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.)

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. 147.
Parent taxa Cactaceae > subfam. Opuntioideae > Opuntia Cactaceae > subfam. Opuntioideae > Opuntia > Opuntia polyacantha
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. polyacantha var. arenaria, O. polyacantha var. erinacea, O. polyacantha var. hystricina, O. polyacantha var. polyacantha
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. nicholii, O. hystricina var. nicholii
Name authority Haworth: Suppl. Pl. Succ., 82. (1819) (L. D. Benson) B. D. Parfitt: Cact. Succ. J. (Los Angeles) 70: 188. (1998)
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