20. Astrophytum

Lemaire, Cact. Gen. Sp. Nov. 3. 1839.

[Greek asteros, star, in reference to the star-shaped stem cross section of the type species, and phyton, plant]

Allan D. Zimmerman & Bruce D. Parfitt

Plants stem succulents, unbranched [to several branched from base], mostly low and deep-seated in substrate [taller in Mexican species]. Roots diffuse. Stem unsegmented, dark green or gray-green, hemispheric or depressed-spheric [to spheric or short cylindric], (2.5-)6-15(-60)[-100] × 6-10(-20) cm, speckled [or entirely hidden] by numerous tufts of dense, whitish, multicellular hairs less than 0.5 mm; ribs [4-]8-10, crests uninterrupted, straight [to sinuous and/or helically curving around stem], broad and nearly flat or rounded [sharp or keeled]; areoles distinct, [2-]6-9[-20] mm apart along ribs, circular; areolar glands absent; cortex and pith hard, not mucilaginous. Spines absent [1-25 per areole in some Mexican species]. Flowers diurnal, near stem apex, at adaxial edge of areoles, funnelform, 4.5-5.4[-8] × 3.8-5.2[-6] cm; inner tepals yellow, proximally red [all yellow], 25 × 6-10[-12] mm, margins entire; ovary sparsely to densely scaly, axils spineless long hairy with arachnoid trichomes, distal scales spine-tipped; stigma lobes [8-]10-12, yellow [pale yellowish], 4 mm. Fruits indehiscent or splitting irregularly, green or pinkish to red, ovoid to spheric, 15-20 × 12 mm, initially fleshy, drying immediately after ripening, sparsely to densely scaly with spine-tipped scales; axils of scales long woolly, spineless; floral remnant persistent. Seeds dark brown to blackish, appearing hollow or bowl-shaped from strongly expanded, inrolled rim around sunken hilum, 2-3 mm in greatest dimension, nearly smooth; testa cells very slightly convex. x = 11.

Species 4-5 (1 in the flora): sw United States, Mexico.

Astrophytum is most often recognized as a distinct genus. Chloroplast DNA evidence (C. A. Butterworth et al. 2002), however, confirms that it is among the closest relatives of Echinocactus. Unlike Echinocactus, the stem surfaces of Astrophytum species are speckled by numerous tiny white tufts of minute, matted hairs in addition to the regularly spaced woolly areoles.

1. Astrophytum asterias (Zuccarini) Lemaire, Cactées. 50. 1868.

Star-peyote, star cactus, sea-urchin cactus

Echinocactus asterias Zuccarini, Abh. Math.-Phys. Cl. Königl. Bayer. Akad. Wiss. 4(2): 13. 1845

Plants flat-topped and usually flush with soil surface, or at most, above-ground portion low, dome-shaped. Stems shiny, sparsely speckled by bright white extra-areolar hair tufts 0.5-1 mm diam.; ribs usually 8, straight, very low, nearly flat or rounded; areoles 3-5 mm diam., with yellow or gray wool. Flowers opening widely, externally long woolly; inner tepals lanceolate, acuminate. 2n = 22.

Flowering Mar-May and sporadically after summer rainfall. Grasslands, shrublands, Tamaulipan thorn scrub, gravelly slopes and deep soil of flats; of conservation concern; 20-100 m; Tex.; Mexico (Nuevo León, Tamaulipas).

The vernacular name of Astrophytum asterias, star-peyote, reflects its superficial similarity to peyote, Lophophora williamsii, which has very soft, uniformly pale blue-green stems quite unlike the hard, speckled, almost shiny, green stem surface in A. asterias. Astrophytum asterias is extremely rare and localized north of Mexico, presently known only from Starr County, Texas.

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32. Lophophora

J. M. Coulter, Contr. U.S. Natl. Herb. 3: 131. 1894.

Peyote [Greek lophos, crest, and phoreus, a bearer, in reference to tufts of hairs in areoles]

Allan D. Zimmerman & Bruce D. Parfitt

Plants erect, commonly unbranched, becoming many branched and moundlike in old age, deep-seated in substrate. Roots taproots. Stems unsegmented, usually gray-green or blue-green to dark green [yellow-green in L. diffusa of Mexico], usually flat-topped and cryptic in soil surface, sometimes protruding above it with recessed apex, ribbed or weakly tuberculate, 2-7.5 × (4-)5-12 cm, softly fleshy, soft skinned, dull, glabrous; ribs 5, 8, or 13 (rarely 21), low, broadly rounded, straight, vertical or less often helically curved around stem; areoles 3-15+ mm apart along ribs or at apices of low, humplike tubercles, circular, copiously hairy, hairs usually in compact, erect tufts to 7-10 mm; areolar glands absent; cortex and pith not mucilaginous. Spines absent. Flowers diurnal, deeply nestled in copious areolar hairs at stem apex, arising from adaxial edges of areoles, campanulate, 1-3 × (1-)1.5-2.5 cm; outer tepals whitish to greenish pink, midrib greenish, margins entire or minutely fringed or ciliate distally; inner tepals usually white to pink [rarely yellowish white or magenta to reddish violet, at least in Coahuila, Mexico], 8-14(-22) × (1-)2.5-5 mm, margins ciliate or entire; ovary smooth, scales, hairs, and spines absent; stigma lobes (3-)4-8, white or pinkish, 1-3 mm. Fruits indehiscent, white to pinkish [to purple], clavate to nearly cylindric, 11-25 × (2-)4-5 mm, weakly succulent, quickly drying and contracting after ripening, upon drying becoming translucent and brownish white or whitish, spines and scales absent; pulp colorless; floral remnant weakly persistent or tardily deciduous. Seeds black, somewhat pyriform, cylindric, or obovoid, 1-1.5 × 1-1.2 mm, not glossy, with large, flat hilum; testa cells strongly convex. x = 11.

Species 2 (1 in the flora): arid regions, sw United States, Mexico.

1. Lophophora williamsii (Lemaire ex Salm-Dyck) J. M. Coulter, Contr. U.S. Natl. Herb. 3: 131. 1894.

Mescal buttons, divine cactus

Echinocactus williamsii Lemaire ex Salm-Dyck, Allg. Gartenzeitung 13: 385. 1845; Anhalonium williamsii (Lemaire ex Salm-Dyck) Lemaire

Plants 0-50-branched, nearly flush with soil surface. Roots fleshy, broadly carrot-shaped, 6-12 cm. Stems flat or domelike with deeply depressed center; ribs to 25 mm broad. Flowers: outer tepals narrowly elliptic to oblanceolate, apex acute, mucronate; inner tepals elliptic, margins white to greenish pink, midstripes darker, apex mucronate or attenuate; ovary 3-4.5 mm; styles white, 5-14 mm. 2n = 22.

Flowering Mar-May(-Sep). Chihuahuan desert scrub, Tamaulipan thorn scrub, usually on or near limestone hills; 100-1500[-1900] m; Tex.; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí, Tamaulipas, Zacatecas).

Long used for religious and medicinal purposes by native peoples, Lophophora williamsii is famous for its psychoactive alkaloids, primarily mescaline, which are concentrated in the small, photosynthetic, above-ground portion of the stem. Experienced peyoteros harvest only the top few millimeters of the stem, leaving the deeply recessed apical meristem, thus allowing regeneration. The plants live for many decades and grow very slowly. Anhalonium, a later name for Ariocarpus, has been applied to species of Lophophora, and was widely used in older pharmaceutical literature.

Fruits abruptly ripen up to one year (rarely longer) after flowering.

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31. Ariocarpus

Scheidweiler, Bull. Acad. Roy. Sci. Bruxelles. 5: 491, figs. 1-5. 1838.

[The genus Aria and Greek karpos, fruit, referring to the Aria-like fruit]

Allan D. Zimmerman & Bruce D. Parfitt

Neogomesia Castañeda; Roseocactus A. Berger

Plants erect, unbranched [or branched], deep-seated in the substrate [or somewhat subterranean for whole seasons]. Roots taproots. Stem unsegmented, gray-green (yellow-green or purplish with age or stress), above-ground portion flat, concave, or weakly hemispheric, usually flush with soil surface and cryptic, strongly tuberculate, 0-2(-10) × [3-]5-10(-15) cm, hard, rigid, tough skinned [thin skinned in A. agavoides of Mexico]; tubercles arranged in rosettes or mosaics, ± triangular, 8-20[-60] × [3-]11-25 mm, hard, exposed faces of tubercles strongly differentiated from sides [except in some Mexican species], prominently fissured [wrinkled, roughened, or nearly smooth]; areoles elongate [circular and axillary, circular and subapical, or 2-parted], forming a wide woolly groove on each tubercle; areolar glands absent; cortex and pith not mucilaginous, "mucilage" restricted to elongate cavities. Spines absent [sporadic and rudimentary in some Mexican taxa]. Flowers diurnal, borne in axils of tubercles near stem apex, broadly funnelform to almost salverform, 1.5-5 × 1.5-5 cm; outer tepals brownish or greenish with pink tinge, 12-35 × 5-9 mm, margins entire; inner tepals pink or magenta [white or yellow], 13-34 × 4-10 mm, margins entire; ovary smooth (scales, hairs, and spines absent); stigma lobes 5-10, white, 1.2-5 mm. Fruits indehiscent (very rarely explosively dehiscent), white or cream to pale greenish [reddish], spheric to clavate or cylindric, proximally or almost completely buried in copious wool of stem apex, 10-25 × 5-10 mm, initially fleshy, drying and collapsing a few days after ripening, scales and spines absent; pulp white to pale greenish; floral remnant apparently persistent. Seeds black, spheric to obovoid, 1.2-1.6(-2.5) mm, minutely tuberculate, shiny; testa cells strongly convex (conspicuous with lens). x = 11.

Species 6 (1 in the flora): arid regions, sw United States, Mexico.

Ariocarpus species mostly grow in broken rock substrate and closely mimic it. Some Mexican species display additional adaptations, e.g., A. kotschoubeyanus (K. Schumann) K. Schumann withdraws into seasonally inundated, fine lacustrine soil and can be completely buried between growing seasons.

SELECTED REFERENCES Anderson, E. F. 1965. A taxonomic revision of Ariocarpus. Cact. Succ. J. (Los Angeles) 37: 39-49. Anderson, E. F. and W. A. Fitz Maurice. 1997. Ariocarpus revisited. Haseltonia 5: 1-20.

1. Ariocarpus fissuratus (Engelmann) K. Schumann in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 106[III,6a]: 195. 1894.

Living-rock cactus, star cactus, chaute, chautle

Mammillaria fissuratus Engelmann, Proc. Amer. Acad. Arts 3: 270. 1856 (as Mamillaria)

Varieties 1-3 (1 in the flora): Texas, Mexico.

1a. Ariocarpus fissuratus (Engelmann) K. Schumann var. fissuratus

Plants protruding above ground 0-2(-10) cm. Stems: tubercles forming coarse mosaic, closely packed, exposed faces of tubercles deltoid to hemispheric, deeply fissured on either side of central areolar groove, coarsely rugose, often sharply angled apically; areoles to 3 mm wide, sometimes confined to middle of tubercle faces instead of extending to tips. Flowers 2.5-5 cm diam., 2 times wider than long when fully expanded; inner tepals 21-30 × 5.5-7.5(-10) mm.

Flowering Sep-Nov. Chihuahuan desert scrub, low, rocky hills of limestone chips; 500-1500 m; Tex.; Mexico (Chihuahua, Coahuila, Durango).

The stems of Ariocarpus fissuratus are normally flush with the soil surface and resemble limestone chips in shape, color, and texture, rendering the plants extremely cryptic. The species is often found growing with Agave lechuguilla and species of Leucophyllum, and Parthenium.

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