Eschweilera mexicana T.Wendt, S.A.Mori & Prance
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Authority
Mori, S. A. & Prance, Ghillean T. 1990. Lecythidaceae - Part II: The zygomorphic-flowered New World genera (Couroupita, Corythophora, Bertholletia, Couratari, Eschweilera, & Lecythis). With a study of secondary xylem of Neotropical Lecythidaceae by Carl de Zeeuw. Fl. Neotrop. Monogr. 21: 1-376. (Published by NYBG Press)
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Family
Lecythidaceae
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Scientific Name
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Type
Type. Mexico. Oaxaca: Mun. Santa María Chimalapa, Zona de Uxpanapa, hills to N and E of Arroyo Chocolín, Congregation Nicolás Bravo, to N and E of Rancho Rutt, ca. 3-5 km S of Río Alegre (Veracruz), 17°10'30"N, 94°42'W, elev. 250 m, 16 Jul 1984 (fl), Wendt & Montero 4468 (holotype, MEXU; isotypes, CHAPA, MO, NY, TEX, XAL).
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Description
Description - Trees, to 35 m x 80 cm above buttresses, with small to medium-sized, thick buttresses on larger trees. Bark dark brown, smooth, usually with shallow, sharp-rimmed, irregular depressions and paler lenticels disposed in vertical rows; outer bark very thin; inner bark pale brown or rose-brown when cut; sapwood nearly white. Leaf blades elliptic to narrowly ovate-elliptic, 8-20 x 2.5-7 cm, glabrous, punctate abaxially, subcoriaceous or coriaceous, with 10-15 pairs of lateral veins; apex broadly to narrowly acuminate, the acumen to 1.5(-2) cm long; base rounded to obtuse, very narrowly decurrent; margins entire, often very slightly repand; petiole 8-15 mm long, 1.5-2.5 mm thick, minutely wrinkled when dry; stipules very narrowly lanceolate, 0.5-0.9 mm long, with filiform tip, caducous, obvious only during leaf flush; distal cataphyll of each shoot 1-2 cm long, linear-elliptic, enclosing young shoot, caducous. Inflorescences once-branched paniculate arrangements of racemes, terminal and in upper leaf axils, sometimes (especially axillary ones) unbranched, glabrous, the rachis 2-9 cm long, the lower lateral branches to 4.5 cm long; pedicels 4-6 mm long, the articulation, bracts, and bracteoles inserted within 1 mm of base; bracteoles persistent, suborbicular-ovate, fleshy, 0.5-1.2 mm long. Flowers ca. 4-5 cm diam; calyx with six lobes, the lobes broadly ovate, 3.5-6 x 3-5 mm, carinate and slightly gibbous at base abaxially, concave adaxially, the margins entire, the apex rounded; petals six, white (cream-yellow in bud), broadly elliptic but often revolute and appearing triangular, eventually reflexed, 20-25 x 10-15 mm, glabrous, the apex rounded, the margins entire or with scattered, thick, short (0.1 mm long) cilia; hood of androecium yellow, 15 x 17 mm wide, forming a distinct double coil, the appendages narrowly deltoid, angular, to 6 mm long; staminal ring slightly elevated on disk 1 mm high on ligular side, with 130-160 stamens, the filaments 1-1.8 mm long, slightly swollen at apex, the anthers 0.5 mm long; ovary 2-locular, each locule with ca. 8-10 basally attached ovules, the style 0.5-1 mm long, very broadly obconical, not well differentiated from summit of ovary. Fruits with 1-6 seeds, cupshaped to very broadly turbinate, 2.5-5 x 4-6.5 cm, broader than long, the pericarp ca. 2 mm thick when dry, the calycine ring 1/3-½ distance from base. Seeds 2.7-4.3 x 2-3.5 cm, hemispherical or triangular (rarely round) in crosssection depending on number of seeds per fruit, dark chestnut brown with pale veins when fresh, paler when dry, with lateral, poorly developed aril. Germination from opposite ends of seed; seedlings with several squamate cataphylls below eophylls, the eophylls very obscurely dentate, with minute, marginal hairs to 0.5 mm long.
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Discussion
Eschweilera mexicana differs from its geographically nearest congener, E. hondurensis Standl., by its more coriaceous leaves, larger fruits (2.5-5 x 4-6 vs. 1.4-3.5 x 2-4 cm), and lack of persistent pedicel on the fruit. A further analysis of their affinities awaits flowering collections of the latter species.
The stamens of the staminal ring on the ligular side are elevated on a slight disk 1 mm high. We have not observed this in any other species of Eschweilera.Eschweilera mexicana is the first species of Lecythidaceae documented for the Mexican flora (Prance & Mori, 1979), and also represents an apparent disjunction of the genus from Honduras. A former report that Grias cauliflora (cited as either of its synonyms, G. fendleri or G. integrifolia) occurs in Mexico is based on a misidentification of Amphitecna regalis Lindl., a large, simple-leaved Bignoniaceae (Williams, 1939; Standley & Williams, 1962).The Uxpanapa area appears to be a center for endemism that may have served as a refuge area for rain forest species during the Pleistocene and perhaps longer (Wendt & Lott, 1985). The discovery of E. mexicana there supports this hypothesis.Distribution and Ecology: Known only from lowland rain forests on both sides of the Veracruz-Oaxaca border in the southern part of the Uxpa-napa area. Eschweilera mexicana is locally very common but apparently occurs in relatively isolated populations within larger areas of seemingly appropriate habitat. It is restricted to the steep, hilly, southern portion of Uxpanapa, where it grows only on hilltops in deep soil as a codominant in rain forest in which other common tree species are Dialium guianense (Aubl.) Sandw., Terminalia amazonia (J. F. Gmel.) Ex-ell, Licania hypoleuca Benth., Symphonia globulifera L.f., Ormosia panamensis Benth., Calophyllum brasiliense Camb. var. rekoi Standl., Tapirira sp., and Pouteria spp. Neither flowering nor fruiting seems to be highly synchronous. Flowering, observed to date only in July, was only in a few individuals. Both immature and mature fruits, on different trees, have been observed from May through October. Leaf flush following leaf drop was observed in December. Although the fruit is freely operculate, fallen fruits without the operculum and containing germinating seeds have often been observed.
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Common Names
cajita, jicarillo
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Distribution
Mexico North America| Veracruz Mexico North America|