Basic Literatur

Fig. 1. Inflorescence of Echeveria prolifica (M19133) 21 May 1975.

ECHEVERIA PROLIFICA A New Species from Mexico

REID MORAN & JORGE MEYRÁN

At a small roadside nursery near the Hidalgo-Puebla boundary, Meyrán and Felipe Otero in 1969 found a small unknown echeveria with bright yellow flowers. The vendor said it was from a cañada just to the north, and Meyrán and some companions returned twice to seek it there, without success. The plant may well be there, perhaps very local and because of the rugged terrain and abundant vegetation very difficult to find. Thus the report of the vendor can be neither discounted nor fully accepted; and the source of the plant remains uncertain.

This attractive plant may also bear seeds but normally spreads by stolons and also multiplies abundantly by the small leaves of the floral stems, which fall at the slightest touch and grow new plantlets. It is thus making its way in the garden world, even threatening to become a greenhouse weed, and so needs a name. Considering how freely the Mexican Crassulaceae cross, the question may be raised whether it could be a garden hybrid. Aside from the fact that no prospective parents come to mind, Dr. Charles H. Uhl reports none of the irregularity in meiosis that would be very probable in a hybrid. There is thus no reason to doubt that it is a native species; and we therefore describe and name it.

Fig. 2 Rosette of E. prolifica with young apparently floral stems, 21 May 1975. X 1.0.

Echeveria prolifica Moran & Meyrán, sp. nov.

Planta glabra, stolones ramis floriferis similes emittens. Rosulae subsessiles 4-8 cm latae, foliis 20-40 glaucis cuneato-obovatis cuspidatis 2-4 cm longis. Rami florferi graciles 15-25cm alti 20-30-foliati, foliis facile cadentibus radicantibusque. Cyma conferta ex 2-5 cincinnis 2-4 floratis constans, pedicellis ca. 1mm longis. Sepala subadpressa subaequalia obovata obtusa 3 mm longa. Corolla lutea prismatico-campanulata vix angulata 5-6 mm longa. Typus: Meyrán 3462 (MEXU). Species ad E. amoenae L. de Smet et E. microcalyci Brit. et Rose proxima sed ab eis foliis latioribus cuspidatis, inflorescentia compacta, corolla breviore lutea, praesentiaque stolonum bene distincta.

Fig. 3. Mother rosette of E. prolifica with daughter rosette still attached by stolon, 18 April 1970. Also note plantlets from fallen leaves. X 0.6.

Plant glabrous. Caudex short, simple or commonly stoloniferous, 4-7 mm thick; stolons like floral stems, 15-22 cm long, 1.5-2 mm thick, with ca. 20-30 scattered leaves and a terminal rosette, rooting at several distal nodes. Mature rosettes dense, 4-8 cm wide, of 20-40 leaves. Leaves light glaucous green, often pink-tipped, turgid, obovate-cuneate, obtuse to rounded, cuspidate, 2-4 cm long, 10-16 mm wide above, 3-5 mm wide at base, 4-8 mm thick, rounded dorsally, slightly keeled towards apex, convex ventrally, the margins obtuse to narrowly rounded. Floral stems February to June, weakly erect or becoming decumbent, pale glaucous green, becoming reddish, 15-25 cm tall, 2-2.5 mm thick below, slightly thinner above, with (10-) 20-30 leaves but mostly bare by anthesis. Stem leaves ascending and subventrally attached, obovate-cuneate or the upper narrower and more elliptic, acuminate, 7-13 mm long, 4-8 mm wide, 2-3 mm thick, biconvex with narrowly rounded margins, readily detached and rooting to form new plantlets. Inflorescence a compact cyme 2-3 cm wide, of 5-18 flowers on 2-5 crowded cincinnal branches, each with (1—) 2-4 flowers; pedicels ca. 1 mm long and thick. Calyx cup-shaped, 2-4 mm long, 6-7 mm wide, truncate to subumbilicate below, the disk 2.5-3 mm wide, the segments upcurved, with tips ca. 0.5-1 mm from corolla, somewhat unequal, oblong to obovate, obtuse, 2.5-3 mm long, 1.5-2.5 mm wide, 1-1.25 mm thick above, ca. 0.5 mm thick at base, biconvex with obtuse margins. Corolla in bud subglobose-obtuse, with petals imbricate, at anthesis yellow, greenish medially above, prismatic-campanulate but scarcely angled, with tips slightly outcurved, 5-6 mm long, 4-5 mrn wide below and 5-7 mm above. Petals ovate, broadly acute, somewhat apiculate, 2.5-3.5 mm wide, connate ca. 1 mm or less, flattish and low and obtusely keeled above, keeled to depth of nearly 2mm below, but thin and hollowed with indistinct nectar cavity, gibbous at base. Filaments yellow, ca. 4-5 mm long from corolla base, the epipetalous adnate ca. 1 mm, ca. 0.6 mm wide, the antesepalous ca. 0.5 mm wide; anthers yellow, ca. 1 mm long. Nectar glands yellowish, 1-1.5 mm wide and 0.3-0.5 mm high. Gynoecium 4.5-6 mm high, 2-3 mm thick, the ovaries nearly distinct, green, 3-4 mm high, 1-1.5 mm thick, obtusely keeled dorsally, the styles yellowish, distinct, slender, 1.5-2 mm long or to 3 mm in age. Ovules ca. 38, ca. 0.4 mm long and 0.2 mm thick. Chromosomes: n=33.

TYPE: Bought at Venta Grande, Puebla, on the Mexico-Tuxpan highway SW of Huauchinango, México (near 20°10'N, 98'05'W), in 1969; said to have come from the cañada just to the north; grown in Mexico City and San Diego; Meyrán 3462 (=Moran 19133): holo-type, MEXU; isotypes, ENCB, SD, and to go.

DISTRIBUTION: Known only from the type collection and its teeming progency.

From a plant of the type collection of E. prolifica, Dr. Charles H. Uhl reports a gametic chromosome number of n=33. He found meiosis regular.

Stolons and floral stems start among the rosette leaves and at first are indistinguishable. The stolons become identifiable as such when they persist and the mother rosette grows beyond their attachment to the caudex. Undoubtedly, they are modified floral stems. However, it is uncertain whether each stolon starts out to be a stolon, starts to be a floral stem but for some reason fails to flower, or just starts to be whatever it can.

Fig. 4. Old and young inflorescences of E. prolifica, 18 April 1976. X 1.8.

Echeveria prolifica seems most closely related to E. amoena de Smet and E. microcalyx Britt. & Rose, both native in east central Mexico. These likewise are rather small plants with small flowers, and the cauline leaves are easily detached and will readily root and form new plants. Again the cymes are of a few cincinni, the sepals are short, blunt, and subappressed, and the corolla is scarcely angled. Also, Dr. Uhl found n=66 in E. amoena and n=33 in E. microcalyx. In view of these similarities, we place E. prolifica as a third species in the series Paniculatae Berger, for which Walther (1959) named E. amoena lectotype.

Echeveria amoena and E. microcalyx evidently are very close, if indeed distinct. Echeveria prolifica differs from them in several respects: the plant is stoloniferous; rosette and stem leaves are relatively broader and more cuspidate; pedicels are much shorter and the inflorescence therefore compact; and the corolla is shorter and relatively broader and is bright yellow rather than deep pink.

REFERENCE

Walther, Eric. 1959. Echeveria: conspectus serierum. Leafl. West. Bot. 9: 1-4.