RESURRECTION OF CREMNOPHILA

(Crassulaceae)

REID MORAN

Natural History Museum, San Diego

In the latest generic revision of the Crassulaceae, Berger (1930) divided the family into six subfamilies, among them the Sedoideae, with the (implied) type genus Sedum and the American group Echeverioideae, with Echeveria. Walther (1936, 1972) restricted the Echeverioideae to plants with lateral floral stems, excluding Altamiranoa, Villadia, and Lenophyllum, placed there by Berger. I refer to the Echeverioideae in this restricted sense. Berger's six subfamilies, even with this re­finement, are not all strong and distinct. As a case in point, the boundary between the Eche­verioideae and the Sedoideae is rather uncer­tain. In the Echeverioideae the petals are al­most always united at the base, mostly erect, at least in the lower half, and often thick; the floral stem is axillary; and the plants are often relatively large; whereas in the Sedoideae the petals are mostly distinct or nearly so, wide-spreading, and thin; the floral stem usually is terminal; and the plants commonly are smaller. However, these distinctions are far from abso­lute. Within the large and diverse genus Sed­um, various species have the petals erect and/ or more or less united at the base; various species have lateral floral stems; and various species are relatively large.

In particular, certain Mexican species (sub-genus PACHYSEDUM [Berger] Clausen) tradi­tionally kept in Sedum because of their flowers are more or less Echeveria-like in size and habit, with axillary floral stems. To judge from hybridizations and cytogenetic study (Uhl 1966, 1967, 1976), these species are closely related to the Echeverioideae and so are close to the boundary between the two subfamilies. In fact, PACHYSEDUM seems not only more closely related to some Echeverioideae than to such distant members of Sedum as the sub-genera TELEPHIUM and RHODIOLA but actually closer than to most Mexican members of Sedum. Thus the best taxonomic placement of these species is a problem.

Fig. 1. Cremnophila nutans (Sedum cremnophila). Plant from south of Tepoztlán (Meyrán 1012), 10 December 1960. X 0.8.

The indistinctness of the boundary might suggest that the Echeverioideae be included in the Sedoideae; and since there is a similar if lesser problem as to the boundary between the Sempervivoideae and the Sedoideae, the Sempervivoideae might also be included. How­ever, such a combination of subfamilies would help nothing. Although the Sedoideae may closely approach the Echeverioideae on the one hand and the Sempervivoideae on the other, the Echeverioideae and the Semper­vivoideae are entirely separate and distinct from each other. The Sedoideae are a central group from which the other subfamilies radiate in various directions. And since the Echeveri­oideae are quite distinct from the other sub­families except for the Sedoideae, it seems use­ful and therefore reasonable to keep this group separate, whether as a subfamily or at some lesser rank.

The problem of the boundary between the Echeverioideae and the Sedoideae remains dif­ficult. A particular aspect of this problem is considered here in detail.

Sedum cremnophila

The genus Cremnophila was proposed by Rose (Britton & Rose 1905) for Sedum nutans Rose, a Mexican plant with rosettes and lat­eral floral stems as in Echeveria but with ro­tate flowers as in Sedum. The inflorescence is a narrow thyrse, rare in either genus; and it normally is nodding even in age, in which it appears almost unique. The distinction of this plant from Echeveria is clear enough, but its removal from Sedum has seemed more difficult to justify. Although it is among the most Echeveria-like of those Mexican plants with Sedum-like flowers, still it does not differ im­pressively in this respect from plants whose inclusion in Sedum has never been questioned. On this much evidence, Cremnophila appears a rather weak genus; and Praeger (1921) Berger (1930), Walther (1931), Fröderström (1936), and Clausen (1943, 1959), all have kept it in Sedum. Because of an earlier homo­nym, Clausen renamed the species Sedum cremnophila.

Clausen (1959) wrote that S. cremnophila appeared most closely related to S. dendroideum DC.: "It has the same habit of growth and also has axillary floral stems. Its leaves are similar in shape, but thicker. In heavily shaded situations, the stems become elongate and pen­dulous, as do those of S. dendroideum.... It appears to be a more specialized member of the group of species to which S. dendroideum belongs."

Fig. 2. C. nutans. Plant from above Tepoztlán (M10174), flowering 27 February 1972.

In fact, S. dendroideum is not the closest relative of S. cremnophila, as appears below; and the two differ in many ways, including habit. Sedum cremnophila has a trailing most­ly unbranched caudex, roughened with leaf scars and bearing a rather close rosette of leaves; whereas S. dendroideum is a normally erect and much branched shrub, sometimes more than 2 meters tall and with a trunk di­ameter of 1 dm. or more, with smooth stems and with more separated leaves. The leaves of S. cremnophila are thicker and often wider, with broadly rounded margins, and the at­tachment is broader, often with small lateral entering veins besides the main central one. The floral stem of S. cremnophila is strongly differentiated from the caudex, being smooth and smaller in diameter and bearing reduced and more scattered leaves; and it is constricted at the base and finally deciduous by abscission. That of S. dendroideum is scarcely differenti­ated from the vegetative stems, being of like diameter and at first bearing similar leaves, so that they can scarcely be told apart; and it either withers in place or remains in part to grow as a vegetative branch. The inflorescence of S. cremnophila is commonly nodding, a nar­row thyrse whose somewhat zigzag axis bears a prominent protrusion at each node like a backward extension of the next internode. The branches are joined to these protrusions, and they are reflered with relation to the stem apex and in the nodding inflorescence there­fore ascending with relation to the horizontal. The inflorescence of S. dendroideum, though with more branches and flowers than usual in Sedum, is otherwise quite remarkable; it is not narrow, nor is it nodding with reflexed branch­es, nor are the branches borne on nodal pro­trusions of the axis. The flowers of S. cremno­phila, like those of S. dendroideum, are rather unspecialized; and no major differences are evident.

Uhl (1976) reported gametic chromosome numbers of 33 for Sedum cremnophila and 30, 34, 35, and 36, for S. dendroideum in the broad sense of Clausen (1959). [Clausen (1975) narrowed his concept of S. dendroideum.] In a hybrid of S. dendroideum (n=34) with S. cremnophda, Uhl found 31 to 33 bivalents plus multivalents and 1 to 5 univalents at Metaphase I. He also found meiosis nearly normal in hybrids of S. cremnophila with S. cuspidatum Alexander and S. lucidum Claus­en, both with n=34. He therefore concluded that S. cremnophila is rather closely related to these three plants. However, it differs from these three, and apparently from all other species of Sedum, in its large thick leaves with rounded margins, its deciduous floral stems, and its peculiar inflorescence as described above.

Fig. 3. C. nutans. Thyrse (Meyrán 1012). 19 Janu­ary 1961. X 1.0.

Echeveria linguifolia

Echeveria linguifolia Lemaire is a plant grown for over a century but only recently re­discovered in Mexico (Moran 1968b). It has been kept in Echeveria by all writers treating that genus, including Britton and Rose (1905), Berger (1930), von Poellnitz (1936), and Walther (1972); but it is anomalous in Echeveria (Moran 1968a, 1968b). The large thick leaves with broadly rounded margins are not closely matched in other species but are more reminiscent of Pachyphytum. The floral stem is constricted at the base and finally deciduous by abscission, whereas in other species it re­mains attached, the stump sometimes persist­ing several years. As in no other species, the inflorescence is a narrow pendent thyrse, with reflexed branches jointed to nodal protuber­ances. The sepals are erect, appressed to and nearly equalling the corolla; in most species the sepals are more or less spreading, and if erect, they often are much shorter than the corolla. The petals are essentially free rather than united at the base and are thinner than in other species, with no indication of the nec­tar pit present in thick-petalled species. Though erect, the petals are narrowed upward and not in contact to form a corolla tube as is usual in Echeveria — though petals and sepals together do form a tube. Most remarkable of all, the petals in bud, though imbricate above, are induplicate-valvate in the lower two-thirds; the petals are imbricate in all other species except E. calycosa Moran and E. valvata Mo­ran, where they are valvate. In fact, the in­duplicate-valvate condition appears to be unique in the family. This combination of unique and unusual characters sets E. linguifolia well apart from all other species placed in Echeveria and suggests that it might best be removed from the genus. I concluded (Mo­ran 1968a) that so long as it was kept in Echeveria, it should at least be placed in a series of its own; and I established the INDUPLICATAE for it.

Sedum cremnophila and Echeveria linguifolia Rose (1916), Berger (1930), Walther (1931, 1936, 1972), and others, have com­mented on the great similarity between Sedum cremnophila and Echeveria linguifolia — which in the classification of Berger (1930), it should be noted, fall in different subfami­lies. Walther (1936, 1972) thought E. lingui­folia the most primitive member of the genus and suggested (1931) that "possibly the trans­ition between Echeveria and the more primi­tive genus Sedum may be sought in this vicinity."

In size and general aspect, S. cremnophila and E. linguifolia are indeed much alike. Note­worthy are the decumbent roughened stems, the very thick leaves with broadly rounded margins, the basally constricted floral stems, which finally abscise, the commonly pendent thrysoid inflorescence, with zigzag axis, nodal protuberances, and reflexed branches, and the essentially free petals. The two plants are na­tive on similar cliffs at about the same eleva­tion and only 24 km. (15 miles) apart. The two differ in various details but chiefly in their petals, which in S. cremnophila are imbricate in bud and later widespreading and in E. linguifolia are induplicate-valvate below in bud, remaining erect. Also, the nectar glands are much wider than high in E. linguifolia, as in other Echeverioideae, but about as high as wide in S. cremnophila. The attitude of the petals is the key character that has somehow arbitrarily thrown these two in different genera and different subfamilies. Walther (1936) wrote that were it not for the erect petals, E. linguifolia might with almost equal propriety be placed in Sedum. Of course, a few species of Sedum do have erect petals.

Uhl (1966, 1967, 1976) reported a gametic chromosome number of n=33 in both S. cremnophila and E. linguifolia; and he gave strong evidence that this number is not polyploid but effectively diploid. In hybrids between these species, he found meiosis essentially normal and pollen 75-90 percent normal in appear­ance. Likewise, in second-generation backcross progeny, he found nearly normal meiosis. Among nearly 500 diploid hybrids of Mexican Crassulaceae that Uhl has studied cytologically, those between S. cremnophila and S. linguifolia are one of only five combinations known to be at all fertile. The cytogenetic evidence thus very strongly supports the morphological: he concludes that the reationship between S. cremnophila and S. linguifolia is much closer than is implied by their placement in different subfamilies or even in different genera.

Fig. 4. Cremnophila linguifolia. Plant from Barranca de Mericapa (E. Matuda), flowering 13 January 1974. X 0.4.

What Genus?

Thus the evidence strongly suggests that S. cremnophila and E. linguifolia belong together in one genus — but what genus? The most ob­vious possibilities are Echeveria, Sedum and Cremnophila, where one or the other has been placed before; but related genera must also be considered.

Sedum cremnophila and especially E. linguifolia resemble the genus Pachyphytum, and particularly the section PACHYPHYTUM, in sev­eral characters, including some by which they are anomalous in Sedum and Echeveria. In Pachyphytum the leaves are always thick, with rounded margins; and such species as P. bracteosum Klotzsch (section PACHYPHYTUM) are very similar to S. cremnophila and E. linguifolia in size and habit, with trailing stems and with similar rosettes of similar leaves. In most mem­bers of Pachyphytum, the floral stem usually is deciduous after flowering. The sepals are erect and appressed to the corolla, and in section PACHYPHYTUM they exceed it in length. The petals are rather thin and so lack a well-de­veloped nectar cavity; and they are valvate to slightly open at the base, though mostly im­bricate above. The ventral petal scales distinc­tive of Pachyphytum have inverted vascular bundles (Leinfellner 1954) and thus seem de­rived from infolded lower petal margins; and especially in view of other evidence of rela­tionship, the inturned lower petal margins unique to E. linguifolia may perhaps be re­garded as homologous. In section PACHYPHY­TUM the basic chromosome number is x=33 (Uhl & Moran 1973), the same number as in S. cremnophila and E. linguifolia (and also in some members of Echeveria, Sedum, etc.). And Uhl (1976) has hybridized S. cremno­phila and E. linguifolia with various species of Pachyphytum (as with other members of the Mexican comparium). Unfortunately, he has had for cytogenetic study no hybrids of E. linguifolia with the most similar species of sec­tion PACHYPHYTUM.

Some points of the resemblance of these two to Pachyphytum may be unimportant; and Pachyphytum differs greatly in its inflores­cence, which is normally a single cincinnus. Nevertheless, the overall resemblance is im­pressive and, taken with the ability to hybri­dize, suggests rather close relationship — per­haps closer than with Echeveria. Especially because of the induplicate petals, E. linguifolia by itself might perhaps best be removed from Echeveria to a separate subgenus of Pachyphytum. However, S. cremnophila, which must go with E. linguifolia and which must be as closely related, has no floral charac­ters to justify placement in Pachyphytum.

Fig. 5. C. linguifolia. Thyrse of plant from Mexicapa, 23 January 1974. X 1.0.

Sedum cremnophila and E. linguifolia like­wise resemble Graptopetalum amethystinum (Rose) Walther in several ways. That plant again is similar in size and habit, with trailing stems and with similar rosettes of similar leaves. The floral stem is ascending to de-flexed, with zigzag axis, slight nodal protuber­ances, reflexed branches, and a basal constric­tion where it finally abscises. The gametic chromosome number is n=34 as compared to n=33 in the other two (Uhl 1970).

In other species of Graptopetalum, floral stems are mostly persistent. The habit varies from sessile solitary or cespitose rosettes to shrubby; but all species have rather similar flowers, the petals imbricate in bud, ascending to spreading from near the middle in anthesis, ventrally marked with red mostly in irregular transverse stripes, and mostly united at the base, the stamens reflexed in age, the styles short. The group thus seems a natural genus. The flowers of S. cremnophila and E. linguifolia are quite different and so give no reason for placing either species in Graptopetalum — where G. amethystinum clearly belongs. The rather remarkable similarities of these two spe­cies to G. amethystinum and to Pachyphytum are perhaps in part a parallelism somehow re­lated to their cliff habitat. In fact, the cliff habitat of E. linguifolia was tentatively pre­dicted from the similarities (Moran 1968a)!

Though traditionally kept in Echeveria, E. linguifolia by itself, as explained above, might better be removed to Pachyphytum. And if E. linguifolia is anomalous in Echeveria, S. crem­nophila would be even more so because of its spreading petals and its nectar glands as long as wide — in addition to the anomalous charac­ters shared with E. linguifolia. Thus there is no logic for placing S. cremnophila in Eche­veria.

Because of its Sedum-like flowers, S. crem­nophila has traditionally been kept in Sedum despite its divergent habit and inflorescence. As the largest and most diverse genus of the family, Sedum has always been a repository for anomalies; and since a separate genus can scarcely be made for every borderline species, Sedum will continue to be so. Therefore, if S. cremnophila were kept in Sedum, a case might be made for transferring E. linguifolia also to Sedum, where it might seem scarcely less at home than in Echeveria. However, such a treatment would ignore the seeming rela­tionship of E. linguifolia (and hence of S. cremnophila) to Pachyphytum. Although such judgements are subjective, it appears that S. cremnophila is already beyond the bounds tor Sedum and that the more divergent E. linguifolia would be even more so.

From this rather subjective evaluation I conclude that E. linguifolia and S. cremno­phila belong together in one genus but do not both conveniently fit into any of the genera considered. I therefore place them in their own genus, which must be called Cremnophila (Moran 1975). Cremnophila is distinct morphologically, particularly in the form of the inflorescence, but is very close to Sedum subgenus PACHYSEDUM. From the standpoint of generic definition, it seems unfortunate that S. cremnophila does not share the most dis­tinctive character of E. linguifolia, the induplicate aestivation of petals.

The resurrection of Cremnophila, bringing together two closely related species that do not fit well in any other genus, seems a step forward. However, it is by no means a com­plete solution to the generic problem in this part of the family. The evidence of Uhl (1976) strongly suggests that species of Sed­um subgenus PACHYSEDUM are more closely related to the Echeverioideae, and particular­ly to Cremnophila, than to various members of Sedum. Thus the present treatment of PACHYSEDUM seems unsatisfactory; and the group needs further evaluation as to limits, relationships, and best taxonomic placement.

Fig. 6. C. linguifolia. Inflorescence details, plant of long-cultivated clone (M10998), 9 February 1965. X 1.8.

TAXONOMY

Cremnophila Rose in Britton & Rose, N. Amer. Fl. 22: 56. 1905.

Echeveria section Clavatae E. Walther, Cact. Succ. J. 8: 83, 85. 1936. Name only.

Echeveria series Induplicatae Moran Cact. Succ. J. 40: 36, 1968.

Glabrous succulent perennials. Caudex elongate, soon decumbent or pendent, somewhat branching, subterete but roughened, each node flattened or with V-shaped transverse groove to 3mm deep. Leaves ± rosulate, turgid, 2-4 times wider than thick, with rounded margins, contracted to narrow attachment with one main entering vein and often 1-2 small laterals. Floral stems axillary, taking over 6 months to develop, much thinner than caudex and smooth, with scattered reduced leaves, flower­ing in winter and early spring, constricted at base and in age abscising; inflorescence a narrow arch­ing to pendent thyrse; axis zigzag, each node with retrorse protrusion like backward extension of next axial segment; branches joined to axis, reflexed (i.e. ascending in pendent thyrse), each a cincinnus of 1-6 flowers, or the lower branching and each with 2-3 cincinni; pedicels short. Flowers 5-merous. Sepals erect to ascending, appressed to corolla, unequal. Petals thin, distinct or nearly so, either imbricate throughout and becoming rotate, or induplicate-valvate below and remaining erect.

1. Cremnophila nutans Rose, N. Amer. Fl. 22: 56. 1905.

Sedum nutans Rose, Bull. New York Bot. Gard. 3: 43. 1903. Not S. nutans Haworth, 1821.

Sedum Cremnophila Clausen, Cact. Succ. J. 15: 63. 1943. Based on S. nutans Rose.

Caudex to 8dm long, 1-2.8cm thick, pale green and somewhat shining, becoming brown, the leaf sites oval, the attachment scar elliptic, ca. 4-10mm wide and l-2mm high. Rosettes compact to lax, 10-17cm wide, of 12-25 leaves. Leaves green or grayish but not glaucous, oblanceolate-spatulate to rhombic-obovate, somewhat oblique, rounded to broadly acute and apiculate, 4-10cm long, 2-5.5cm wide, 7-17mm thick, slightly convex to shallowly concave ventrally, convex dorsally, obliquely low keeled, the base ca. 1cm wide. Floral stems first appearing in summer (?), flowering between Jan­uary and April, pale or yellowish green, 1-2.5dm long (including inflorescence), the peduncle stiff, erect to deflexed, 6-14cm long, 6-9mm thick at base, with 6-20 leaves; leaves ascending, oblong to obovate, rounded, 12-25mm long, 8-18mm wide, 4-8mm thick, flattish ventrally, with rounded mar­gins. Thyrse mostly arching to pendent, light green, 5-13cm long, 3-5cm wide, of ca. 30-90 flowers, the branches 10-35, the lower few often each with 2-3 cincinni, the upper each of one; dncinni to 2cm long, each with 1-6 flowers, scarce­ly circinate, the buds erect. Pedicels l-4mm long, ca. 1mm thick. Calyx disk ca. 2.5-3mm wide, the ..... Stamens 10. Nectar glands slightly longer than wide to much shorter. Pistils multiovulate, erect, united at base. tapering to slender styles. Chromo­somes: x=33.

TYPE SPECIES: Sedum nutans Rose, by original designation.

The genus is placed in the subfamily Echeverioideae, close to Pachyphytum Link, Klotzsch, & Otto.

Rose (Britton & Rose 1905) noted for C. nutans: "The flowering stem usually hangs down and the secondary branches stand up, but in herbarium specimens the reverse is sug­gested; in cultivated specimens the flowering stems are nearly erect." Likewise, in plants of C. linguifolia hanging from their native cliff, the peduncle points downward and the thyrse is pendent (cf. Moran 1968b, fig. 43). In erect young plants of both species, whether on cliffs or in flower pots, the peduncle is necessarily more nearly erect; but the somewhat flexible thyrse is usually arching or pendent. However, in some cultivated plants of C. nutans, in some years, the thyrse remains nearly erect, as re­ported by Rose, segments erect in bud and after anthesis, ascend­ing between petals at anthesis, often markedly un­equal, oblong, obtuse, 3-7mm long, 1-2.5mm wide, the sinuses narrowly V-shaped. Corolla near chal­cedony yellow, rotate, 11-14mm wide, the petals distinct, ovate to elliptic, acute with subdorsal mucro, 4-7mm long, 2-3.5mm wide, in bud imbricate throughout. Filaments yellow, ascending, ca. 4.5-5mm long and 0.5mm wide at base, the epipetalous adnate ca. 1mm; anthers yellow, 0.9-1.3mm long. Nectar glands orange, obovate, truncate or subemarginate, ca. 0.8-1.0mm long, 0.8-0.9mm wide, 0.25mm thick. Gynoecium yellow, ca. 5mm high and 2.5mm thick, the pistils connate ca. 0.6mm, the styles 1.5-2.0mm long, well separated by second day; ovules 35-45, cylindroid, ca. 0.6 x 0.2mm. Fruit and seeds not seen. Chromosomes: n=33.

TYPE COLLECTION: Mossy cliffs at Tepoztlán, Morelos, 2250m, 8 February 1899, C. G. Pringle 6980 (US 48383).

Fig. 7. Dissected flowers of C. nutans (left), hybrid, and C. linguifolia. Photo by Howard Lyon.

DISTRIBUTION: Known only from cliffs to the north and south of Tepoztlán, Morelos, at ca. 1800-2300m. See Clausen (1959). Collected south of Tepoztlán by J. Meyrán (1022, SD) and by C. H. Uhl (2435, BH).

ILLUSTRATIONS: Addisonia 1: pl. 25; Cact. Succ. J. 8: 87; Succulenta 1959: 139; Cact. Suc. Mex. 3: fig. 12; Clausen, Sedum of the Trans-Mexican volcanic belt, fig. 23.

2. Cremnophila linguifolia (Lemaire) Moran, Baileya 19: 145, 1975.

Echeveria linguaefolia Lemaire, Ill. Hort. 10: misc. 81. 1863.

Talinum linguaeforme Hort. ex Lemaire, loc. cit, as synonym.

Anacampseros linguaefolia Hort. ex Lemaire, loc. cit., as synonym.

Cotylendon linguaefolia Hort. ex Lemaire, loc. cit., as synonym.

Cotyledon linguaefolia (Lemaire) Baker, in Saunders, Refug. Bot. 1: pl. 58. 1869.

Pachyphytum Lingua Hort. ex. Baker, loc. cit., as synonym.

Caudex to 1m or more long, 1-2.5cm thick, green becoming brown, the leaf sites oval, ca. 10-12mm wide and 7-9mm high, the attachment scar elliptic, brown, ca. 5-7mm wide and 1-2mm high. Rosettes lax, 6-17cm wide, of 15-25 leaves, or the leaves sometimes as many as 40 and scattered over as much as 2.5dm of caudex. Leaves green and not glaucous, obovate or obovate-cuneate to oblong-spatulate, rounded to obtuse, 4-9cm long, 1.5-5.5cm wide, 7-14mm thick, flattish to slightly con­cave ventrally, convex to rounded dorsally, in some faindy keeled, the base 8-13mm wide, 6-12mm thick. Floral stems first appearing May to July, flowering between December and May, light green, 1.5-3.5 (-5.5) dm long (including inflores­cence), the peduncle stiff, ascending to deflexed, 1-2.5 (-4)dm long, 5-11mm thick at base. with 4-20 leaves; leaves somewhat ascending, elliptic-ob­long, obtuse to rounded, 1.5-3.5cm long, 8-19mm wide, 4-12mm thick, convex ventrally, rounded dorsally. Thyrse flexible, pendent, glaucous, 6-16cm long, 3-6cm wide, of ca. 20-70 flowers, the branches 15-35, the upper ones and often a few lowermost one-flowered, the rest cincinni of 2-5 flowers each, somewhat circinate. Pedicles 2-4 (in solitary and terminal flowers -10)mm long, 1-2mm thick. Calyx 6-13mm long, 4.5-9mm wide, the disk ca. 4-6mm wide, the segments erect, somewhat unequal, triangular-lanceolate, rounded to subacute, 4-12mm long, 1.5-5mm wide, very slightly imbricate in young buds but soon open, the sinus­es narrowly V-shaped with sides parallel above, closed after anthesis. Corolla white or greenish, pentagonal with ± flat sides, 6-11mm long, 4-7mm wide, the petals nearly distinct though slightly united by the adnate filaments, erect, triangu­lar-lanceolate, acute, keeled, 2-4mm wide, in bud induplicate-valvate in lower two-thirds, imbricate above. Filaments greenish white, 5-8mm long, ca. 0.7mm wide at base, the epipetalous adnate ca. 1mm, the antesepalous ca. 0.5mm; anthers light yellow, ovoid, apiculate, ca. 1.5mm long. Nectar glands yellowish green, appressed against the pis­tils, ca. 1.5mm wide and 0.4mm high. Gynoecium green, 5-10mm high, 3-4mm thick, the pistils con­nate ca. 1mm, the styles 2-3mm long, remaining erect; ovules 80-120, cylindroid, ca. 0.6 x 0.2mm. Follicles nearly erect, papery, pale. Seeds clavate, light brown, 0.6-0.7mm long, 0.25-0.3mm thick, reticulate in ca. 16-18 longitudinal rows. Chromo­somes: n=33.

TYPE COLLECTION: The species was described from a sterile plant grown in Belgium, with no information as to origin; specimen unknown. Walther (1972: 63) reprinted plate 58 of Baker (1869) and designated it neotype for the species.

DISTRIBUTION; Known from only two localities in the southern part of the State of Mexico. Collections: Edo. de Mexico: common on sheer north-facing cliffs just SW of Malinalco, 1900m, Moran 14778 (HNT, INIF, K, MEXU, MICH, NY, SD, UC, US); Barranca de Mexicapa, E. Matuda as living plant (Moran 19134, SD).

ILLUSTRATIONS: Saunders Refug. Bot. 1: pl. 58 (reprinted in Walther, Echeveria, fig. 16); Cact. Succ. J. 8: 87, 40:37; Succulenta 1959: 140; Cact. Suc. Mex. 13: figs. 43-45; Wal­ther, Echeveria, figs. 16-18.

Lemaire (1863) named this species from a sterile plant of unstated origin grown in Bel­gium, later (1864) adding the description of a rather depauperate inflorescence. The descrip­tions leave little doubt as to the identity of his Echeveria linguaefolia with the plant still grown under this name. Baker (1869) fully described and beautifully illustrated what is unquestionably the plant grown today, saying it came from a Belgian nursery. It seems a reasonable assumption that Baker had the same plant as Lemaire; and his plate is thus a good choice for neotype. Baker gave the na­tive land as Mexico.

REFERENCES

Baker, J. G. 1869. [The American species of Co­tyledon (Echeveria DC.)] Refug. Bot. 1: pls. 56-71 [and letterpress without page numbers].

Berger, Alwin. 1930. Crassulaceae. In Engler, die natürlichen Fflanzenfamilien ed. 2. 18a: 352-485. Wilhelm Engelmann, Leipzig.

Britton, N. L., and J. N. Rose. 1905. Crassulaceae. N. Amer. Fl. 22: 7-74.

Clausen, R. T. 1943. A new name for Rose's Sedum nutans. Cact. Succ. J. 15: 63-84.

—— 1959. Sedum of the trans-Mexican volcanic belt. Cornell Univ. Press, Ithaca.

—— 1975. Sedum of North America north of the Mexican Plateau. Cornell Univ. Press, Ithaca.

Fröderström, Harald. 1936. The genus Sedum L., part 4. Acta Horti Gothob. 10 (Appendix).

Leinfellner, Walter. 1954. Beiträge zur Kronblattmorphologie. III. Die Kronblätter der Gattung Pachyphytum. Oesterr. Bot. Z. 101: 586-591.

Lemaire, Charles. 1863. Histoire, espèces et cul­ture du genre Echeveria. Ill. Hort. 10: misc. 76-84.

—— 1864. Floraison de l'Echeveria linguaefolia Nob. Ill. Hort. 11: sub. pl. 393.

Moran, Reid. 1968a. New subgeneric groups in Echeveria and Pachyphytum. Cact. Succ. J. 40: 36-42.

—— 1967. Chromosomes of Sedum cremnophila, Cact. Suc. Mex. 13: 67-70, 85.

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© Cactus & Succulent Journal of America, 1978