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FNA | Family List | FNA Vol. 4 | Cactaceae

3. Grusonia F. Reichenbach ex K. Schumann, Monatsschr. Kakteenk. 6: 177. 1896.

Club-cholla [for Hermann Gruson, 1821-1895, German engineer, and his Magdeburg plant collections]

Donald J. Pinkava

Corynopuntia F. M. Knuth; Marenopuntia Backeberg; Micropuntia Daston; Opuntia Miller subg. Corynopuntia (F. M. Knuth) Bravo; Opuntia sect. Clavatae Engelmann; Opuntia ser. Clavatae (Engelmann) K. Schumann

Shrubs, usually densely branched, forming mats or clumps [erect or decumbent]. Roots tuberlike and/or diffuse, also often adventitious. Stem segments firmly attached in most species in the flora to easily dislodged, cylindric-clavate, usually curving upward from near bases, sometimes subspheric, subequal in length, glabrous, strongly tuberculate, sometimes appearing ribbed; areoles ± circular, 1-6 mm diam.; wool white, gray, or yellow. Spines with epidermis sheath deciduous at apices only, exposing yellow spine tips; at least 1 of major spines in distal areoles angular-flattened to ribbonlike, sometimes cross-striate, sometimes bulbous based. Glochids commonly increasing greatly in number with time, in distal areoles, white, yellow, or brown. Flowers bisexual, radially symmetric; inner tepals bright yellow or rose to purple. Pollen spinulo-punctate, not reticulate (cylindropuntioid type). Fruits yellow to brownish, narrowly obconic to ellipsoid when fertile, fleshy at first, soon drying, smooth, sometimes spiny; areoles bearing conspicuous tuft of long, white to tan wool. Seeds yellowish white or pale yellow to brownish, suborbicular (to rectangular) or flattened, 3-6 mm, smooth or with rows of raised bumps; funicular girdle encircling seeds, not protruding. x = 11.

Species 14 (8 in the flora): s United States, n Mexico.


Pinkava, D. J. 1999b. Cactaceae cactus family: Part 4. Grusonia.... J. Arizona-Nevada Acad Sci 32: 8-52.

1 Flowers rose to purple; spines of fruits hairlike, flexible, antrorsely barbed (high magni- fication)   8 Grusonia pulchella
+ Flowers yellow; spines of fruits, when present, more rigid, retrorsely barbed   (2)
2 (1) Major adaxial spine(s) of distal areoles terete to subterete or absent; shrubs forming mats or clumps; roots tuberlike   (3)
+ Major adaxial spines of distal areoles angular-flattened, at least at bases; shrubs forming mats; roots diffuse   (4)
3 (2) Major adaxial spine(s) of distal areoles white to brown to black (but not rich red-brown) or absent; longest central abaxial spine commonly twisted or curved, completely chalky white (at least adaxially) except in basal 3 mm or less   1 Grusonia aggeria
+ Major adaxial spines of distal areoles rich red-brown (or tan); longest central abaxial spine usually straight, brownish, and cross-banded with interrupted, whitish, wavy lines   2 Grusonia grahamii
4 (2) Tubercles very prominent, broad, 1-3.5 times longer than wide, not or little obscured by interlacing spines   (5)
+ Tubercles prominent, narrow, 4-6 times longer than wide, obscured by interlacing spines   (6)
5 (4) Stem segments 7-19 × 2.5-5 cm; distal tubercles 25-50 mm   3 Grusonia emoryi
+ Stem segments (2-)3.5-6.5 × (1.5-)2-3 cm; distal tubercles 8-20 mm   4 Grusonia schottii
6 (4) Mature fruits very spiny and glochidiate; plants to 50 cm, in series usually 2-4 stem segments.   5 Grusonia kunzei
+ Mature fruits not spiny but glochidiate; plants to 20 cm, in series usually 1-2 stem segments   (7)
7 (6) Stem segments 2.5-5(-7.5) cm; distal tubercles 5-10(-16) mm; spines of distal areoles tan or white; longest abaxial spine white, daggerlike, broadly tapered; New Mexico   6 Grusonia clavata
+ Stem segments 5-9 cm; distal tubercles 15-25 mm; spines of distal areoles blackish or brown to tan; longest abaxial spine brown to white, narrowly tapered; Arizona, California, Nevada   7 Grusonia parishii

Lower Taxa


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