Living Rocks of Mexico
A Preliminary Revision of the North American Species of Cactus, Anhalonium and Lophophora
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The paper reproduced here is abridged from Contributions From the U. S. National Herbarium 3(2):91-132. (1894). The sections relating to Ariocarpus/Anhalonium species are reproduced in their entirety. The complete text can be downloaded as a zip file Coulter zip


Lake Forest University, Lake Forest, Ill., January, 1891.

Anhalonium  Lem. Cact. Gen. Nov. (1839)

Depressed or flattened, simple, unarmed plants, covered with peculiar imbricated tubercles above and their scale-like remains below: tubercle with lower and upper parts very different; lower part comparatively thin and flat; upper exposed part triangular in outline and divergent, very thick and hard, the lower surface smooth and keeled, the upper surface plane or convex, smooth or tuberculate or variously fissured, with a broad wool-bearing groove or simply a more or less evident tomentulose apical areola: spine-bearing areola obsolete: flower-bearing areola at the summit of the lower peduncle-like portion of the very young tubercle (thus appearing axillary with reference to the exposed part of the tubercle) and bearing a dense penicellate tuft of long soft hairs which conceals the lower part of the flower and the entire fruit and persists about the apical region of the plant as matted and apparently axillary wool: ovary naked: seeds large, black, and tuberculate: embryo obovate, straight.

According to the present views concerning generic limitations in Cactaceae, Anhalonium must certainly be kept distinct from Mamillaria, and to such a view Dr. Engelmann had finally come. The generic distinction is based upon such characters as (1) the complete suppression of the spine-bearing areolae;(2) the strong differentiation of the tubercles into two very distinct regions;(3) the production of the flower at the apex of the basal or penduncle-like portion (which becomes flattened and expanded at maturity) of a very young tubercle; and (4) the large tuberculate seeds.

In the case of engelmanni the broad woolly groove of the upper portion of the tubercle expands below into the flower-bearing areola, but terminates blindly above just behind the sharp apex.In prismaticum and furfuraceum the groove is obliterated, but there usually remains a small (more or less tufted) areola and depression just behind the apex to mark its upper extremity. This apical areola therefore, does not represent a spine-bearing areola, but the closed upper extremity of a tubercle groove.

It seems evident that Anhalonium is a much modified Cactus, and that its affinity is with the coryphanths, through such a species as C. macromeris, in which the flower becomes extra-axillary. If in macromeris, with the flower standing well up on the tubercle, the portions of the tubercle above and below the flower should become very different from each other, the upper portion being so much modified as to cause the spine-bearing areola to be obliterated, the condition of things in Anhalonium would be obtained.

* Upper surface of tubercle with a broad and deep wool-bearing longitudinal groove which widens below. 

1. Anhalonium engelmanni Lem. Cact 42 (1839)  

Mamillaria fissurata Engelm. Syn. Cact. 270 (1856).

Anhalonium fissuratum Engelm. Bot. Mex. Bound. 75 (1859).

Depressed globose or flat, top-shaped below and tapering into a thick root, 5 to 12 cm. in diameter: tubercles (upper portion) appressed-imbricate, 12 to 18 mm. long and about as wide at base, the upper surface convex and variously fissured (presenting an irregular warty appearance) even to the edges: flowers apparently central, about 2.5 cm. long and broad, shading from whitish to rose: fruit oval, pale green, about 10 mm. long: seeds 1.6 mm. long. (Ill. Bot. Mex. Bound. t. 16). Type unknown; but specimens of Wright, Bigelow, and Parry in Herb. Mo. Bot. Gard. are the basis of Engelmann's Mamillaria fissurata.

On limestone hills, in the "Great Bend" region of the Rio Grande in Texas, and southward into Coahuila.  Fl. September-October. Specimens examined: Texas (Wright of 1850; Bigelow of 1852; Parry, with no number or date; Lloyd of 1890; Evans of 1891; Briggs of 1892): also growing in Mo. Bot. Gard. 1893.

This species is very closely related to the Mexican A. kotchubeyi Lem. (A. sulcatum Salm-Dyck), but unfortunately no type of that species seems to be in existence, and Dr. Engelmann notes (Mex. Bound. Rep. 75) that "it seems no living or dead specimen is at present extant in Europe."  Judging from the description, the upper surface of the tubercles in A. kotchubeyi, aside from the central furrow, is smooth; at least the margin is "very entire." 

** Upper surface of tubercle not grooved, but usually with a tomentose pulvillus at the tip.

2. Anhalonium prismaticum Lem. Cact. 1 (1839)

Mamillaria prismatica Lem. Hort. Univ. i. 231 (1839).

Cactus prismaticus Kuntze, Rev. Gen. Pl. 261 (1891).

Flat above, top-shaped below, 7.5 to 12.5 cm. in diameter: tubercles (upper portion) close]y imbricate but squarrose- spreading, sharply triangular-pyramidal and very acute (with a sharp cartilaginous tip, which usually disappears with age and leaves the older tubercles blunt or retuse), 18 to 25 mm. long and about as wide at base, the upper surface almost plane and smooth, except that it is more or less pulverulent and usually bears a small tomentose pulvillus (often evanescent later) just behind the claw-like tip: flowers rose-color: fruit elongated- oval and reddish. (Ill. Lem. Cact. t. 1.)Type unknown.

Referred to Mexico in general, but reported definitely only from San Luis Potosi. Undoubtedly found in Coahuila, and possibly crosses the Rio Grande in the region of the "Great Bend."  

Specimens examined: San Luis Potosi (Eschanzier of 1891): Mexico in general (specimens from Coll. Salm-Dyck in 1858; Schott of 1858): also specimens cultivated in Mo. Bot. Gard. in 1881; also growing in same garden in 1893. 

3. Anhalonium furfuraceum (Watson)

Mamillaria furfuracea Watson, Proc. Amer. Acad. xxv. 150 (1890).

Very closely related to prismaticum; but triangular portion of tubercle acuminate and shorter, having an irregularly mamillate upper surface, and the acumination ending abruptly in a cartilaginous depression containing a tomentose pulvillus: flowers 2.5 to 3 cm. long, white or pinkish, the sepals brownish. Type, Pringle 2580 in Gray Herb.

At Carneros Pass, Coahuila.

Specimens examined: Coahuila (Pringle 2580 of 1889).

The type of this species was not among the collections received from Cambridge, but a specimen of the same distribution from the National Herbarium shows tubercle dimensions different from those recorded in Dr. Watson's description.  In that description the triangular terminal surface is said to be "about an inch broad by one-half inch," which is decidedly different from the equilateral surface of the tubercle of prismaticum. In the National Herbarium specimen of furfuraceum, however, of the same distribution, the surface is almost equilateral, measuring 15 mm. long by 18 mm. wide at base. Without the acuminate upper portion the breadth of the triangular portion would be about double its length. The lower rim of the cup-like depression which terminates the tubercle and contains the pulvillus is sometimes slightly prolonged into a tooth, which in prismaticum becomes the sharp tip of the tubercle. The "minutely furfuraceous-punctulate" character of the tubercle is common to all the species of Anhalonium I have seen, and simply represents the external openings of the remarkably long cuticular passageways to the stomata.

4. Anhalonium pulvilligerum Lem. Cact. (1839)

Anhalonium elongatum Salm-Dyck (1850). 

This seems to be a third grooveless Mexican species. I have seen no specimens, but judge from the description that it differs from the two preceding species chiefly in its less crowded and more elongated tubercles (triangular portion 5 cm. long by 2.5 cm. broad at base), which are covered at apex with a tomentose pulvillus.

Geographical distribution

This curious genus is strictly Mexican, and, so far as at present recorded, is characteristic of Coahuila, but a single species (engelmanni) of the four or five known crossing the Rio Grande in the Great Bend. 

Lophophora, gen. nov.

Depressed-globose, proliferous and cespitose, tuberculate-ribbed, unarmed plants: tubercles at first conical and bearing at summit a flower-bearing areola with a dense tuft or short pencil of compact erect hairs, when mature becoming broad and rounded (with the remnant of the penicellate tuft as a persistent pulvillus in a small central depression) and coalescing into broad convex vertical ribs: spine bearing areolae obsolete: flowers borne at the summit of nascent tubercles: ovary naked (that is free from scales, but often downy): fruit and seed unknown.  

These forms have been variously referred to Anhalonium and Echinocactus, but seem to deserve generic distinction. They differ from Anhalonium in the entire suppression of the upper highly differentiated portion of the tubercle, in the broad and rounded development of the lower portion, and in the coalescence of the enlarged tubercles into broad vertical ribs. In fact, in young specimens, the plant appears almost smooth, with shallow furrows radiating from the depressed apex. The genus differs from Echinocactus in the suppression of the spine-bearing areolae, and the naked ovary. In the examination of developing tubercles the relation to Anhalonium is evident. In the latter genus the young tubercle bears on the summit of its pedicel-like lower portion the tufted flower-bearing areola the modified upper portion of the tubercle at that time appearing as a bract beneath the flower. In Lophophora there is the same condition of things, except that the bract-like upper portion is wanting. From this point of view it would appear that the differences between Lophophora and Echinocactus are intensified by the fact that the flower-bearing areola in the former genus is to be regarded as really lateral on a tubercle the upper part of which has disappeared. This genus occurs abundantly in southeastern Texas, extending southward into Mexico. Mrs. A. B. Nickels reports that the Indians use the plants in manufacturing an intoxicating drink, also for "breaking fevers," and that the tops cut off and dried are called "mescal buttons."

1. Lophophora williamsii  (Lem) 

Echinocactus williamsii Lem. Allg. Gart. Zeit. xiii. 385 (1845).

Anhalonium williamsii Lem. in Forst Handb. Cact. i. 233 (1846).

Hemispherical, from a very thick root, often densely proliferous, transversely lined below by the remains of withered tubercles: ribs usually 8 (in young specimens often 6), very broad, gradually merging above into the distinct nascent tubercles which are crowned with somewhat delicate penicellate tufts, which become rather inconspicuous pulvilli on the ribs: flowers small, whitish to rose: stigmas 4.(Ill. Bot. Mag. t. 4296) Type unknown.

Along the Lower Rio Grande, Texas, and extending southward into San Luis Potosi and southern Mexico.

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