VILLADIA ARISTATA (CRASSULACEAE),

A NEW SPECIES FROM NORTHEAST MEXICO

REID MORAN

California Academy of Sciences San Francisco, CA 94118


Abstract. From Texas to Peru, Villadia Rose has some 40 species. Although its boundary with Sedum is unclear and needs refinement, Villadia seems best kept separate as a taxonomic conve­nience. V. aristata (sect. VILLADIA) is unique in its narrow-mouthed ellipsoidal mostly white corolla with irregularly denticulate rounded segments, each with a subapical spur up to a third its length. In V. cucullata Rose the corolla has similar segments but is even more closed and is subtruncate at the apex, it is red to orange, and it lacks the spur. C. H. Uhl reports n = 10 in V. aristata and n = 11 in V. cucullata.


In November 1957 I visited the Sierra de Alvarez, San Luis Potosí, with George Lindsay and Charles Mieg in search of the elusive Minas de San Rafael and Ferocactus rafaelensis—both of which did elude us that trip. However, we did find other plants of interest, at least to me, in­cluding the little-known Echeveria lutea (Moran 1962) and a less-known, and in fact unknown, Villadia. This last I re-collected in 1962 and with Charles Uhl in 1966, and he collected it again in 1970. Several collections flowered in San Diego to be duly described, photographed, and pressed for the herbarium, and in Ithaca, where Mitsu Nakayama drew their flowers (Fig. 4) and Dr. Uhl counted their little chromosomes (Fig. 5). Being a perfectionistic taxonomist, however, I didn't want to rush into anything and so briefly put off naming this new species in the hope of first learning more about the genus. Now that I am a civilian or layman or whatever a retired botanist becomes, with little prospect of further fieldwork in Mexico, I realize that I may never know more about Villadia than right now and in fact am forgetting fast. So whether I am now less responsible or just more practical, or perhaps just have an irrepressible urge to write for this celebrated journal, I want to put down what I know about this plant before forgetting that too.



Fig. 1. Flowers of Villadia aristata (M 6323), 7 June 1958, x 5.


Villadia


Villadia is a group of Sedum-like plants found from Texas to Peru and probably beyond but especially in Mexico. Jacobsen (1974) uncriti­cally listed some 40 species, and if a few of these belong in synonymy or in Sedum, perhaps as many more await naming. Unlike more spectac­ular relatives centering around Echeveria, Vil­ladia has scarcely caught the attention of growers or, for that matter, of botanists either. Some of us with a broad interest in the family have run across them in Mexico and southward and have of course brought them home to grow and won­der about, but never since Dr. Rose founded the genus 87 years ago has anyone given them special study. Yet they are an intriguing group, deserving more attention. In a preliminary report on 19 species, Uhl (1963) found 15 different gametic chromosome numbers, from 10 to 89; so they are cytologically diverse and interesting, and chromosome numbers may be very helpful.


Yes, Villadia would be an interesting study for someone, but I have too many unfinished proj­ects already. However, I do want to put on record, a few interesting discoveries and so have been doing a little spadework.



Fig. 2. Type plant of V. aristata (M 10006) flowering in San Diego, 19 July 1963, x 0.5.


One unanswered question is whether to uphold the genus Villadia and, if so, how to define and limit it. Rose (Britton and Rose, 1903, 1905) founded it for eight Mexican species he was then naming as new and three formerly named in Cot­yledon. These are herbaceous or suffrutescent pe­rennials, several with thickened roots, most with narrow leaves, all with fairly small flowers in spikes or narrow thyrses and with petals united at the base. At the same time, Rose proposed Altamiranoa for 12 other Mexican species, three described as new and nine formerly in Sedum or Cotyledon. They are something like Villadia but with a broader inflorescence, of a few spreading cincinni. However, in such species as V. minutiflora Rose the inflorescence may be somewhat intermediate when the axis of the thyrse is short and the cincinnal branches relatively long.


In the latest generic revision of the Crassulaceae, Berger (1930) kept both Altamiranoa and Villadia, and also Lenophyllum, as genera of his newly founded subfamily Echeverioideae. He added eight Peruvian species to Altamiranoa and moved A. goldmanii Rose to Villadia. Walther (1936) restricted the Echeverioideae to plants with lateral floral stems, thus excluding Altamiranoa,



Fig. 3. Rosettes of V. aristata (M 10006), 4 May 1963, x 1.


Villadia, and Lenophyllum; and later students of the family have agreed (e.g., Uhl, 1963). Fröderström (1936) treated Altamiranoa but did not deal with Villadia; and he kept A. goldmanii in Altamiranoa.


Baehni (1937) united Altamiranoa with Vil­ladia, arguing that if there were no difference other than in the inflorescence, there was no more reason for keeping these two separate than for dividing Echeveria in two on the same basis. (He might have added that the small genus Leno­phyllum, undoubtedly natural, also has the same gamut of inflorescence types.) Walther (1938) used the same argument but took up "Altami­ranoa" for the combined group. Clausen (1940) again combined the two, for the same reason, but showed a flaw in Walther's case and agreed with Baehni in calling the combined genus "Vil­ladia"; he made Altamiranoa a section of Vil­ladia. That is a good argument for combining Altamiranoa and Villadia if they are indeed clos­est relatives and if there are no other differences, as all seem to assume and as may in fact be true; but no one has really addressed that question.


Villadia and Sedum


Sedum is so large and heterogeneous that thor­oughgoing differences from other genera are often hard to find. The only obvious distinction be­tween Sedum and Villadia sect. ALTAMIRANOA is in the degree effusion of the petals, a character usually given much weight in this family: petals are nearly free in Sedum and are united in Vil­ladia usually for a quarter or more of their length. Clausen (1959) in fact separated Sedum and Vil­ladia for his part of Mexico only by the length of the corolla tube—less than 1.0 mm in Sedum and more than 1.2 mm in Villadia. He even transferred to Villadia one species he himself had earlier described in Sedum, as well as one Fröderström had named in Sedum. Because some species have much smaller flowers than others, relative length of the corolla tube seems a better criterion than actual length.



Fig. 4. Flowers of Villadia aristata (M 6323). A. Part of spike, x 5. B. Corolla segments with stamens, x 12. C. Corolla segment, x 12. D. Tip of corolla segment, showing spur, x 12. E. Gynoecium and nectar glands, x 15. Drawing by Mitsu Nakayama, July 1958.


The line between Villadia sect. ALTAMIRANOA and Sedum thus is at least hard to draw if not quite arbitrary, and authors have not agreed where to draw it. Fröderström (1936) kept seven of Rose's twelve species in Altamiranoa but re­turned the other five to Sedum. Likewise, Clausen (1981, 1984) placed in Sedum the four of these five that grow in his area. Furthermore, Fröderström remarked that the species of his Group SUBCAMPANULATAE of Altamiranoa [with four more of Rose's original species] came near to Sedum and might be placed there, close to Sedum bourgaei Hemsl. "But at the same time they have so much in common with [his Group GAMOPETALAE] that a separation would seem un­natural." For the GAMOPETALAE, including V. batesii (Hemsl.) Baehni & Macbr., type species of Altamiranoa, he described the corolla tube as longer than the lobes.


Clausen (1959) described two natural hybrids of species of Villadia sect. ALTAMIRANOA with species of Sedum; but in view of the wide crossability of Mexican Crassulaceae. documented es­pecially by Uhl (1976, etc.), this would not be surprising even if Villadia and Sedum were more distinct than they are, which apparently they are not.



Fig. 5. Meiotic chromosomes of V. aristata (M 10006) at metaphase I, x 2,000, showing 10 pairs; preparation and photo by C. H. Uhl.


On the other hand, the relationships of Vil­ladia proper (i.e., sect. VILLADIA) are less clear. The species are not so obviously related to any particular group of Sedum, standing apart in their spicate to thyrsoid inflorescences. By Clausen's (1959) test of corolla tube length, some species might go into Sedum, yet no one has ever put them there. For example, although on the Mex­ican Cordilleran Plateau some small-flowered species of sect. VILLADIA may have corolla tubes shorter than 1 mm, Clausen (1981,1984) did not place them in Sedum. Villadia might make a stronger genus by itself than united with Alta­miranoa, which is less easily separable from Se­dum. For the present, however, I see no con­vincing reason for separating Altamiranoa from Villadia.


In trying to evaluate the genus Villadia once before (Moran, 1971), I remarked that although it seemed ill-defined if not artificial, some of the species with corolla tube equalling the lobes would seem quite out of place in Sedum as usually con­ceived. The species of Villadia needed to be stud­ied in comparison with various species of Sedum to see where their relationships lay and whether sharper generic lines could be drawn. Accepting the fact that genera in this family often are not well marked arid distinct, however, I would con­tinue to recognize Villadia as a taxonomic con­venience pending such a study.


A New Species


Villadia aristata Moran, species nova


Rosula hiemalis 1-2.5 cm lata 30-50-foliata, vere in caulem floriferum strictum 1-3 dm altum excrescens; folia 30-100 elliptico-oblonga acuta basi calcarata 8-16 mm longa 2-3.5 mm lata, apicem versus murico-papillosa; spica 3-20 cm alta 1-1.5 cm lata 12-100-florata, floribus subsessilibus; sepala subaequalia lanceolata 3.5—4.5 mm longa; corolla alba ellipsoidea 4-5 (-7) mm longa, segmentis cochleari-obovatis rotundatis fimbriatisque, 3.1-3.7 (-4.5) mm longis, uno-quoque dorsaliter apicem versus calcari 1-1.4 mm longo instructo. Typus: Moran 10006 (SD). Species corolla subclausa segmentisque calcaratis insignis, V. cucullatae corollae segmentis rotundatis denticulatisque similis quae autem corolla rubra clausa apice subtruncata non calcarata differt.


Glabrous but papillose perennial, with her­baceous stems dying nearly to base after flow­ering, the new shoots appearing at base before old ones die. Roots mostly 2-3 mm thick, some to 5 mm. Winter rosettes dense, 1-2.5 cm wide, of ca. 30-50 leaves, growing out in spring to form the floral stems. Stems erect, 1-3 dm tall, 1.5-4 mm thick, smooth, often red-lineolate, with ca. 30-100 leaves below inflorescence, mostly unbranched below but sometimes with one or more erect branches to 10 cm tall. Leaves ascending, grayish green, oblong-lanceolate to -oblanceolate, acute, spurred, 8-16(-27) mm long, 2-3.5 mm wide, 1-2(-3) mm thick, flattened or some­what channeled ventrally, rounded dorsally but somewhat keeled at apex, muricate-papillose to­wards apex especially on margins and keel, often with low-conical dorsal protrusion near apex, the margins obtuse above, subacute below, the spur rounded to bluntly triangular, extending 1-2 mm below leaf attachment, the attachment oval, 0.6-0.9 mm wide, 0.4-0.5 mm high, the bundle scar subcircular, 0.15-0.2 mm wide. Inflorescence 3-20 cm tall, 1-1.5cmthick.of ca. 12-100 flowers, subspicate or subthyrsoid, some of lower and middle branches then being two-flowered. Bracts similar to stem leaves but smaller and diminish­ing upwards, the lower twice the length of flow­ers, the upper about equalling calyx, more mark­edly concave ventrally and with acute margins. Pedicels mostly less than 1 mm long, with two lateral bracteoles similar to bracts but smaller. Calyx cup-shaped, the sepals subequal, free to base but scarcely spurred, imbricate at base, broadly lanceolate, acute, 3.5-4.5(-5) mm long, 1.5-2 mm wide, ca. 0.6-0.9 mm thick, muricate-papillose on margins and towards apex, flattened or somewhat concave ventrally towards base, convex and thicker above, the margins acute, somewhat irregular, thin and colorless over much of their length, the apex often with low-conical dorsal protrusion ca. 0.15 mm high. Corolla ellipsoidal to subglobose, 4-5(-7) mm long (ineluding spurs), 3-4 mm wide, open 1-2 mm at apex, white or pink to lavender above, greenish below; segments imbricate, connate ca. 0.6-0.9 (-1.7) mm, cochlear-obovate, rounded and irreg­ularly denticulate or short-fimbriate at apex, 3.1-3.7(-4.5) mm long (not including spur), 2.2-2.8 mm wide above, ca. 1 mm wide at base, dorsally keeled above, the keel continuing upward from 0.3-0.4 mm below apex as a tapering spur 1.0-1.4 mm long and 0.2-0.3 mm thick at base. Fil­aments whitish, 1.7-2.3 mm long from corolla base, adnate ca. 0.6-0.9 mm, the epipetalous ca. 0.2, the antesepalous ca. 0.3 mm wide; anthers pale yellow, ovate, ca. 0.7 mm long. Nectar glands orange-yellow, paler below, 0.7-0.9 mm long, cuneate and 0.3-0.35 mm wide at base, abruptly widening to 0.55-0.6 mm in upper fourth, emarginate. Pistils green, erect but slightly separated above, 2.2-2.5 mm high, 0.8-1.1 mm thick, con­nate ca. 0.6-0.7 mm, narrowing rather abruptly into thick conic styles ca. 0.5 mm long; ovules ca. 22-28, clavate, ca. 0.4 x 0.2 mm. Follicles brown, erect, ca. 3 mm long and 1.5 mm thick, the suture erect in lower half, thence curving to horizontal at base of style, obovately gaping in upper half, the style recurved. Seeds light reddish brown, narrowly obovoid, 0.5-0.6 mm long, 0.2-0.3 mm thick, covered with tubercles ca. 0.03 long and half as thick, in ca. 16 longitudinal rows. Chromosomes: n = 10. Flowers June to Novem­ber.


TYPE COLLECTION: Rather scarce on limestone under oaks or especially at clearings, ca. 2,350 m elevation, near kilometer 33 on the 1962 road from San Luis Potosí to Rio Verde, west slope of Sierra de Alvarez, San Luis Potosí, Mexico (near 22°06'N, 100°41"W), 22 November 1962, Moran 10006: holotype SD 56956; isotypes, CU, SD and to go: CAS, K, MEXU. NY, US.


DISTRIBUTION: On granite or mostly lime­stone, Coahuila, Nuevo León, San Luis Potosí, and Tamaulipas, at 2,200-3,800 m, and so in several vegetation zones, from oak woodland through coniferous forest to krummholz and open alpine meadow. Representative collections:

COAHUILA. Summit of Sierra la Marta with Pinus culminicola and P. hartwegii, 3,600 m, McDonald & Gómez 1241 (TEX); cliff face, pine-oak woodland, Cerro de la Viga, Mpio. Arteaga, 8,800 ft, S. Sundberg et al. 1767 (TEX); Sierra de Coahuilón, Mpio. Arteaga, 3,240 m, G. B. Hinton 18929 (TEX). NUEVO LEÓN. Infrequent in open alpine meadow in soil weathered from hard gray limestone, summit of Cerro Potosí, 3,650 m, J. H. Beaman 4461 (US); colonies on rocky summit of Cerro el Potosí, 3,810 m, G. B. Hinton et al. 17261 (TEX); common in rocky meadow on ridge with scattered pines and firs and Ceanothus, 3,000 m, Picacho San Onofre, Mpio. Doctor Arroyo, G. Nesom & D. Morgan 6777 (TEX); moss on limestone, forest of Quercus and Pinus ayacahuite, SE slope of Cerro el Viejo, 2,395 m?, Mpio. de Zaragoza, R. T. Clausen 77-27 (CU); in humus on granite, Cerro Delgadito, 2,600 m, between Siberia and Encantada, A. Lau 073, HNT 41306 (BH). SAN LUIS POTOSÍ. Sierra de Alvarez: type locality, Moran 6323 (MICH, SD, UC); 4.4 miles W of Puerto Altamira, 7,200 ft, C. H. Uhl 1843 (BH, SD); lime­stone escarpment and rocks above Mex. Hwy. 70, 2.5 miles W of Puerto Altamira, 7,650 ft, C. H. Uhl 1841 (BH, SD); occasional on rocky bank above road, 2,300 m, 1.3 miles E of Puerto Al­tamira, Moran & Uhl 13358 (SD?); occasional on limestone, Cuevo de los Caballos, 2,500 m (and seen to summit of Cerro de los Caballos, 2,900 m), Moran & Uhl 13375 (SD); crest of ridge with Quercus and Buddleia near microwave tow­er at 2,590 m, Mex. Hwy. 70 E of San Luis Potosí, D. E. Breedlove & F. Almeda 59325 (CAS). TA­MAULIPAS. Crest of ridge at 3,050 m, with Pinus, Populus, Arctostaphylos, Quercus, Agave, and Ceanothus, along logging road NE of Miquihuana and SE of Cerro Peña Nevada, D. E. Breedlove & B. Anderson 63570 (CAS).


Thus recent borrowings from other herbaria show this plant widespread to the north of San Luis Potosí. So far as the dried specimens show, these other collections are essentially similar to the original ones, though some collectors have noted the flower color as pink or lavender instead of white. The distinctive form of the corolla, however, is unmistakable, and for the Lau col­lection from Nuevo León Dr. Uhl also found the distinctive chromosome number of this species (see below). The one collection from Tamaulipas is like the others except that the flowers are con­spicuously larger. The several original collections are nearly uniform in flower size, with corollas 4-5 mm long, whereas in the Tamaulipas plant the corolla is ca. 5-7 mm long.


The detailed description of the species is main­ly from living material from the type region in San Luis Potosí. Because the dried specimens studied more recently do not lend themselves so well to detailed description, I have merely broad­ened the species description with parenthetic ex­tremes for a few measurements.


Relationships


Clearly, V. aristata belongs to the section VILLADIA, or the original genus Villadia, in which the inflorescence is a spike or narrow thyrse (Fig. 2). Within this section some plants of southern Mexico, like V. guatemalensis, V. nelsonii Rose, and V. ramosissima Rose, are suffrutescent, with stems that do not die back to the base after flow­ering and that variously branch above the base; whereas some plants of central and northern Mexico, such as V. cucullata Rose, V. misera (Lindl.) Clausen, and V. stricta Rose, do die back to the often somewhat tuberous base after flow­ering and have only rather strict branches from


the base. Villadia aristata (Fig. 2) falls in the second group—though whether these are natural groups is not clear. Its leaves are generally similar to those of species in this group; and the leaves, bracts, and sepals are muricate-papillose towards the apex, as in some of these species.


Some species of sect. VILLADIA, such as V. guatemalensis, V. pringlei Rose, and V. nelsonii, have the pistils tapering into long slender erect or as­cending styles; whereas several like V. cucullata and V. misera have squat pistils with short styles that in fruit are abruptly outcurved-spreading — or it might be better to say that the upper part of the ovary becomes abruptly outcurved. In V. aristata the styles are of this second type, and these are the species to which it must be related.


Villadia aristata is unique in the genus in that each corolla segment bears a long subapical dor­sal spur or apicula 1-1.4 mm long and so some­times a third the length of the corolla (Figs. 1, 4). Other species lack the apicula or may have a short one, but only to ca. 0.2 mm long—or to ca. 0.5 mm in an unnamed related species.


The new species is remarkable also for its el-lipsoidal corolla, open only ca. 1-2 mm at the apex, with rounded and irregularly denticulate cochlear segments. In most species the corolla is more open, with segments erect or often spread­ing from near the middle, and has slightly erose to entire margins. Villadia cucullata Rose, of northeastern Mexico, also has the corolla closed, with the segments rounded and irregularly den­ticulate. In fact, it is even more closed than in V. aristata, with the segments more cucullate, and is often somewhat truncate at the apex. Also, it is red to orange rather than white to pink or lavender, and it lacks the spur. Villadia cucullata is generally similar in habit, leaves, and inflo­rescence, though tending to be larger: but it dif­fers in chromosome number.


Chromosomes


Dr. Charles H. Uhl writes me that he has found a gametic chromosome number of n = 10 in the type collection of V. aristata (Fig. 5) and in six other collections: Lau 073, Moran 6323, M&U 13358, M&U 13375, Uhl 1841, and Uhl 1843. Out of more than 150 counts in Villadia, he has found n = 10 in only one other collection, of an unnamed species which I think related to V. ar­istata. Also. he has found only one lower number in Villadia, n = 9 in one unidentified collection from Coahuila. For V. cucullata he has found n = 11.


Acknowledgments


I am grateful to the curators at BH/CU, CAS/DS, ROPA, SD, TEX, and US for the use of their specimens and for other courtesies. Dr. Charles H. Uhl as usual has given me valuable information about chromo­somes—and I must apologize to him because the print­ers got Figure 5 upside down. Both he and Myron Kimnach have made useful comments on the manu­script. And Dr. Dennis Breedlove has lent me his un­mounted collections. I thank them all.


References


Baehni, C. 1937. Villadia et Altamiranoa: Étude sur la fusion de deux genres de Crassulacées. Candollea 7: 283-286.

Berger. A. 1930. Crassulaceae. In A. Engler, Die Natürlichen Pflanzenfamilien, ed. 2. 18a: 352-483.

Britton, N. L.. and J. N. Rose. 1903. New or note­worthy North American Crassulaceae. Bull. New York Bot. Gard. 3(9): 1-45.

———. 1905. Crassulaceae. N. Amer. Fl. 22: 7-74.

Clausen, R. T. 1940. Studies in the Crassulaceae: Villadia, Altamiranoa, and Thompsonella. Bull. Torrey Bot. Club 67: 195-198.

———. 1959. Sedum of the Trans-Mexican Volcanic Belt. Cornell Univ. Press, Ithaca, N.Y.

———. 1981. Variation of species of Sedum of the Mexican Cordilleran Plateau. Privately published by Robert T. Clausen, Ithaca, New York. 27 pp.

———. 1984. Sedum (Crassulaceae) of the Mexican Cordilleran Plateau. Gentes Herb. 12: 8-48, figs. 1-11.

Fröderström, H. 1936. The genus Sedum L., Part 4. Acta Horti Gothob. 10(app.): 1-181, figs. 1-1360, pl.1-115.

Jacobsen, H. 1974. Villadia Rose. P. 392-394 in Lex­icon of succulent plants. Blandford Press Ltd., London.

Moran, R. 1962. Echeveria lutea and its discoverer, Carl Purpus. Cact. Succ. J. 34: 8-12, figs. 4-8.

———. 1971. Villadia nelsonii Rose. Cact. Succ. J. 43: 84-87, figs. 1-2.

Uhl. C. H. 1963. Chromosomes and phylogeny of the Crassulaceae. Cact. Succ. J. 35: 80-84.

———. 1976. Chromosomes, hybrids, and ploidy of Sedum cremnophila and Echeveria linguifolia (Crassulaceae). Amer. J. Bot. 63: 806-820, figs. 1-69.

Walther.E. 1936. Phylogeny of Echeveria. Cact. Succ. J. 8: 82-88, figs.

———. 1938. Notes on Crassulaceae: new combi­nations in two genera. Cact. Succ. J. 10: 22-24, figs.


© Cactus & Succulent Journal of America, 1990