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California Academy of Sciences, San Francisco, CA 94118

In April and May of 1974 Alfred Lau found two similar echeverias north of Juxtlahuaca in northwestern Oaxaca, Mexico. The first (Lau 026) grew on east-facing granitic slopes 6 miles east of Tlacotepec, a town 11 km north of Juxtla­huaca. The second (Lau 030) was found on east-facing gypsum cliffs 2 km north of Juxtlahuaca, above a small intensely bluish-green pond called Laguna Encantada ("enchanted lagoon"). The echeverias had clusters of a dozen or more ro­settes, those exposed to direct sunlight with red-der leaf-margins. Among the associated plants at Laguna Encantada were Villadia albiflora, Echeveria nodulosa, Pinguicula gypsicola, Phyodina laui (Commelinaceae), a palm (Brahea dulcis) and an orchid (Epidendrum falcatum). The two populations of echeveria seem similar enough to be included in one species and we name it here as new.

Lau sent plants of his first collection to the Huntington Botanical Gardens, who later sent a plant to Charles Uhl. Dr. Uhl obtained a chro­mosome count and also created hybrids by cross­ing the species with E. cf. hyalina, E. prunina and E. setosa. Lau also sent plants (without a collection number) to Evon Ray of Sacramento, California, who sent two to Moran. When they flowered, he made photographs, a description, and a herbarium specimen. In 1977 and 1981, with Jan Riha and Rudolf Subik, Lau collected more plants at Laguna Encantada, as did Miguel Cházaro, Rudi Dorsch, Myron Kimnach and Martin Negrete in January 1992 and again, with­out Dorsch, in 1993.

Fig. 1. Looking down on Laguna Encantada. Photo: A. Lau.

During the 1993 trip, trying to find other pop­ulations, we explored for some 35 km along the road running southeasterly from Juxtlahuaca to­ward San Miguel Peras, but no trace of our new species was to be seen. The steep cliffs along this road near Juxtlahuaca were of limestone as at Laguna Encantada, but the exposure was south­ern and thus perhaps too sunny for echeverias. We also looked on east-facing cliffs above Río Juxtlahuaca, along the road between Juxtlahuaca and Tlacotepec, but found only what seems to be E. macdougallii, here far out of its recorded range. Unfortunately, because of rain and im­pending darkness, we were frustrated in our plan to walk to the other Lau site six kilometers east of Tlacotepec; we therefore still know that pop­ulation only from a single clone.

Although we include the two populations of E. subcorymbosa in one species, there are no­ticeable differences:

Although the two populations are less than 20 km apart, the intervening hills and valleys have isolated them sufficiently to allow a divergence of characters. Some variation is noticeable in the Laguna Encantada plants, and, though only one clone is known from east of Tlacotepec, vari­ability most probably occurs there also. At pres­ent it seems best to merely record the differences and to consider all the plants a single species. In its small dense rosettes and congested in­florescence, the new species recalls E. derenbergii J. A. Purpus, placed by Walther in his series Pruinosae. Although the one-sided inflorescence resembles the cincinnus of E. derenbergii, it is really not a cincinnus but a raceme, with bi-bracteolate pedicels. The flowers are rather closeset on the axis in relation to their long pedicels, so the lower pedicels surpass the axis of the in­florescence. It is for this unusual, somewhat corymbose, raceme that we name the species E. subcorymbosa (not to be confused with E. x cor-ymbosa, an old hybrid probably no longer cul­tivated). Because of the subsessile rosettes and racemose inflorescence, we place it in the series Racemosae, a diverse, widespread, and most likely polyphyletic group. It does not seem close­ly related to other species, and we have no sug­gestion as to its nearest relatives.

Fig. 2. E. subcorymbosa at Laguna Encantada, with ferns and Selaginella. Photo: M. Kimnach.

Abbey Garden of Carpenteria, California, of­fered plants propagated from Riha's collection but under the name of Echeveria expatriata Rose, a plant which is most likely of hybrid origin. The leaves are indeed similar to those of E. expa­triata, though flatter and red-margined; but the inflorescence is a cymose-like raceme, rather than a cymose panicle, and the sepals are widely ex­panded.

Echeveria subcorymbosa is an attractive little plant, soon filling a pot with its prolific offsets. Exposure to strong light and less frequent wa­terings will encourage compactness and the red­dening of the leaf margins.

Charles Uhl of Cornell University obtained a chromosome count from plants of the first col­lection (Lau 026), finding a gametic chromosome number of N = 29. He has found this number elsewhere in the genus only in E. agavoides and in an unidentified species (MacDougall B-128) from near Mexicalcingo, south of Tlaxiaco, Oaxaca.

Echeveria subcorymbosa Kimnach & Moran, the type collection, Lau 030, Laguna Encantada. 1. Flowering plant, x 1. 2. Leaf, x 1.5. 3. Flower, lateral and apical views, x 2.5. 4. Petal with stamens, x 2.5. 5 Gynoecium, nectaries and pedicel, x 3. Drawing by Ellen Skultin, 1991, funded by the Huntington Botanical Gardens.

Echeveria subcorymbosa Kimnach & Moran, sp.nov.

Planta glabra; rosula subsessilis densa 3-6 cm lata 20-35-foliata, foliis turgidis obovato-spathulatis cuspidatis 1.5-3 cm longis 8-25 mm latis glaucis; caulis florifer 4.5-11 cm altus 2-4 mm crassus 6-12-foliatus, foliis obovatis acutis 8-15 mm longis; racemus 10-15 mm longus 3-12-floratus, pedicellis 1-3 cm longis 2-3-bracteolatis; sepala inaequalia ovata 2.5-11 mm longa; corolla pentagono-ovoidea 8-12 mm longa infra rubra supra lutea. Typus: Lau 030 (HNT). In sectione Racemosae racemo subcorymboso, axe quam pedicel­lis infimis breviore, notabilis.

Fig. 3. Plants of two Lau collections. Left: from east of Tlacotepec; right, from Laguna Encantada. Photo: M. Kimnach.

Plant entirely glabrous. Stems ca. 3(-5) cm long or more, 5-8 mm thick, the epidermis brown. Rosettes 4-6(-30), flattish or slightly concave above because of ascending or upcurving leaves, (3-)4-6 cm wide, compact, with 20-35 leaves; leaves obovate-spathulate, cuspidate, with subobtuse, red cusp 1 mm long or less, 1.5-3 cm long, 8-25 mm wide ca. 8 mm from leaf-apex, ca. 6 mm wide at base, 5-7 mm thick ca. 1 cm from apex, ca. 4 mm thick near base, plane of upper surface sharply or gradually deflexed with­in 3 mm of apex, apical half of both surfaces obtusely keeled, dull or slightly shiny, glaucous-bluish-gray, the lower surface densely red-flecked (less so in Lau 026), the margins obtuse or slightly rounded and usually reddish. Floral stems 4.5-8(-11) cm long, ca. 2-4 mm thick near base, 3 mm thick near apex, glaucous-pink or -red, the leaves 6-12, ascending, elliptic-obovate, acute, attached subventrally, bluntly spurred, 8-15 mm long, 4-7 mm wide, 2-5 mm thick, bluish white often tinged pinkish; inflorescence a raceme of 3-12 flowers, at first corymbose because of the long lower pedicels, the rachis 10-15 mm long; pedicels at first nearly horizontal, later nearly erect, 1-3 cm long, the lowest the longest, 1.5 mm thick at base, 2 mm thick above, each with 1-3 bracts along basal half, these linear-elliptical, acute, prominently spurred, 2-14 mm long, 1-3 mm wide, 0.5-2 mm thick; calyx disc 4-5 mm wide, the sepals ascending, with tips ca. 1-2.5 mm from corolla, unequal, ovate to triangular-lanceolate, acute, (2.5-)5-11 mm long, (1.5-)2-3 mm wide, 1-1.5 mm thick, reddened at apex; corolla ovoid, pentagonal with sides flatfish or slightly channeled, 8-14 mm long, 6-8 mm thick, the opening 3-4 mm wide; petals with abruptly expanded apices, oblong, subobtuse, 3.5 mm wide, often with a blunt subdorsal mucro less than 0.5 mm long, obtusely keeled dorsally, basal half or two-thirds of dorsal side reddish orange, the apical third or half yellow, ventral side yellow, rather flat except for a narrow channel and a roundish nectar pit ca. 1.5 mm wide, connate for ca. 1 mm; filaments yellow or only so toward apex, the epipetalous inserted at upper side of nectar pit, flattened, 4 mm long 0.8 mm wide, the antesepalous adnate for ca. 0.5 mm, terete, 5 mm long, ca. 0.6 mm thick, the anthers yellow, 1.5 mm long, 0.6 mm thick; nectaries whitish, ca. 1.5 mm wide, ca. 0.5 mm high, the secretory face 0.5 mm wide, turned outwards ± parallel with floral axis; gynoecium 5.5-7 mm high, 4.5-5 mm thick, 3 mm thick at base, yellowish above, whiter below, the pistils erect, appressed, terete or flattened on back near base, connate ca. 1.5 mm, tapering to pinkish styles ca. 2 mm long. Gametic chromosome number: n = 29 (Lau 026, determined by Charles Uhl).

Fig. 4. Inflorescence of E. subcorymbosa (Lau 026) from east of Tlacotepec. Photo: C. Uhl.

Type Collection. Mexico: Oaxaca: Laguna Encantada, ca. 2 km N of Santiago Juxtlahuaca, May, 1974, A. Lau 030 (HNT, holotype; MEXU, isotype). Other Collections. Oaxaca: ca. 6 km E. of Tlacotepec, a town 11 km N of Santiago Juxtla­huaca, 1,800 m, on east-facing granite slopes, 1974, A. Lau 026. Huntington B.G. 41273 (BH, HNT, MEXU, paratypes); Laguna Encantada, 1977 and 1981, A Lau, J. Riha & R. Subik s.n., Huntington B.G. 49315 (HNT, paratype); same, Jan. 18, 1992, M. Kimnach, M. Cházaro, R. Dorsch & M. Negrete 3206 (HNT, paratype); same, Feb. 7, 1993, M. Kimnach, M. Cházaro & M. Negrete 3333 (HNT, paratype).


To Evon Ray, Alfred Lau and Jan Riha for plants and data.

© Cactus & Succulent Journal of America, 1994