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staghorn cholla

Habit Trees or shrubs, openly branching at acute angles, to 2 m. Stem segments whorled or subwhorled, purple to green-purple, 4–18 × 1–2 cm; tubercles prominent, elongate-oval, 1–2(–2.5) cm; areoles subcircular, 3.5–4 mm diam.; wool tan to brown, aging gray. Trees or shrubs, sometimes forming clumps or mats, sometimes geophytes, trailing to erect.
Roots

diffuse or tuberlike.

Stems

segmented throughout or only in ultimate branches, succulent (less noticeably so in some Cylindropuntia), often woody, especially toward base, smooth or tuberculate;

areoles cushionlike, circular or nearly so (to linear), usually bearing conspicuous spines and always bearing glochids.

Leaves

of brief duration, promptly deciduous, present only during initial growth of stem segments and flowers [persistent], conic or somewhat flattened, succulent.

Spines

6–8 per areole (1–2 bristlelike spines) increasing with time, well distributed along stem, slightly interlacing with spines of adjacent areoles, short;

abaxial spines usually reflexed, whitish, pinkish to red-brown, lightly flattened, the longest 10–18 mm;

adaxial spines erect or spreading, rich red-brown, gray coated basally, subterete, 6–11 mm;

sheaths grayish, tipped brown or yellow to golden Glochids in small adaxial tuft or crescent, dark yellow, to 1 mm.

slender to stout (to hairlike), terete to strongly flattened, usually smooth, sometimes barbed or roughened, epidermis intact or partly to wholly separating from body of spine as sheath that hangs onto spine.

Flowers

inner tepals yellow-green, yellow to gold or bronze, or red to rose or magenta, spatulate, apiculate;

filaments yellowish green;

anthers yellow;

style whitish to pale bronze;

stigma lobes whitish.

diurnal (opening late afternoon or night in Cylindropuntia fulgida), bisexual (sometimes functionally staminate or pistillate), solitary in areoles [terminal], radially or bilaterally symmetric (flower curved and/or the ovary flattened), sessile, rotate, cup-shaped, or salverform;

flower tube epigynous, short adnate to extension of stem segment surrounding ovary;

nectary at base of style, open or sometimes covered by outgrowths of proximal portion of style base or of flower tube wall as specialized nectar chamber.

Fruits

often proliferating, yellowish green or tinged red to purple, often stipitate, obovate, 25–40 × 10–20 mm, leathery-fleshy, tuberculate or smooth, essentially spineless;

tubercles prominent, at first, subequal in length or proximal ones longer, fertile ones swelling and becoming smooth;

umbilicus to 9 mm deep;

areoles 20–30.

indehiscent, cylindric, ellipsoid, ovoid, or subspheric, sometimes clavate, fleshy, juicy (bleeding), or quickly drying;

perianth and contained flower parts shriveling and abscising basally as single unit including floral cup, leaving deep to almost flat scar (umbilicus) atop fruit.

Seeds

yellowish, polygonal in outline, warped, 3.5–5.5 × 2.5–5 mm, sides nearly flattened with depressions and protrusions to angular subspheric;

girdle smooth or in a groove.

0 (sterile) or 1–400+, yellowish, tan, gray, or brown, flattened to subspheric, 2–7 mm, each completely enclosed by bony funicular envelope, glabrous or sometimes pubescent, its vascular bundle forming girdle around seed, sometimes enlarged and protruding as ridge or wing.

2n

= 22.

Cylindropuntia versicolor

Cactaceae subfam. opuntioideae

Phenology Flowering spring (Apr–Jun).
Habitat Sonoran Desert, desert scrub, flats, washes, rocky hillsides, canyons
Elevation 600-1300 m (2000-4300 ft)
Distribution
from FNA
AZ; Mexico (Sonora)
[WildflowerSearch map]
[BONAP county map]
Throughout New World from near Arctic Circle to Patagonia [Introduced especially in tropical, subtropical, and warm-temperate regions almost worldwide]
Discussion

Cylindropuntia versicolor forms hybrids with C. acanthocarpa var. major, C. arbuscula (= C. ×vivipara), C. leptocaulis (see discussion under 3. C. ×tetracantha), and C. spinosior (= C. ×grantiorum P. V. Heath). Cylindropuntia ×grantiorum, found in eastern to south-central Arizona, is intermediate between the parental species in values for the number of spines per stem areole, stem segment diameter and color, and fruit tubercles. The hybrids between C. versicolor and C. acanthocarpa var. major, which occur in south-central Arizona, have fleshy, tuberculate fruits, often with one or two short permanent spines at apex and longer and more numerous spines per stem areole.

Cylindropuntia versicolor itself may be of hybrid origin.

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

Genera 16, species ca. 350 (5 genera, 66 species in the flora).

All genera of Opuntioideae in the flora have been combined into the genus Opuntia at various times. Recent research findings in morphology, anatomy, palynology, seed characteristics, host-herbivore relations, and chloroplast and nuclear DNA make untenable the maintenance of the single genus Opuntia. Unlike some genera of subfam. Cactoideae, the segregate genera of Opuntioideae are not known to produce intergeneric hybrids.

Identification of the species within subfam. Opuntioideae is difficult, in part because of widespread phenotypic plasticity, interspecific hybridization, polyploidy, and apomixis (clonal seeds and stems), which play important evolutionary roles, particularly in Cylindropuntia and Opuntia. Habit descriptions, color photographs (including close-ups), and meiotic chromosome counts are very helpful in identification of species. Also, good herbarium specimens require at least two or three consecutive stem segments, flowers and/or fruits, and detailed notes on all fresh flower parts and fruits as to color (particularly inner tepals, filaments, fresh stigma lobes, and fruits), shape, and size (because of extensive shrinkage on drying). Spine characters are generally based on well-developed areoles, mostly in distal portions of stem segments. Yellow spines usually turn dark red to black with age, including those on herbarium sheets.

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

Source FNA vol. 4, p. 109. FNA vol. 4, p. 102. Author: Donald J. Pinkava.
Parent taxa Cactaceae > subfam. Opuntioideae > Cylindropuntia Cactaceae
Sibling taxa
C. abyssi, C. acanthocarpa, C. arbuscula, C. bigelovii, C. californica, C. davisii, C. echinocarpa, C. fulgida, C. ganderi, C. imbricata, C. kleiniae, C. leptocaulis, C. munzii, C. prolifera, C. ramosissima, C. spinosior, C. tunicata, C. whipplei, C. wolfii, C. ×kelvinensis, C. ×tetracantha
Subordinate taxa
Synonyms Opuntia versicolor, Opuntia arborescens var. versicolor, Opuntia thurberi subsp. versicolor
Name authority (Engelmann ex J. M. Coulter) F. M. Knuth: in C. Backeberg and F. M. Knuth, Kaktus-ABC, 125. (1935) Burnett: Outlines Bot. 2: 742, 1130. (1835)
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