Mecranium tuberculatum Urb.

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Mecranium tuberculatum Urb.

  • Primary Citation

    Repert. Spec. Nov. Regni Veg. 14: 339. 1916

  • Description

    Description Author and Date: James D. Skean, Jr., January 2011, based on Skean, J. D., Jr. 1993. Monograph of Mecranium (Melastomataceae-Miconieae). Syst. Bot. Monogr. 39: 1-116.

    Type: HAITI. [Dépt. du Sud]: Massif de la Selle, in mountains near Furcy, fl, Nov 1896, Picarda 1516 (holotype: B, destroyed; isotypes: BR! GH-fragment! S!).

    Description: Shrub or small tree to ca 3 m tall. Twigs strongly 4-angled and ridged, 3-4 mm in diameter, often slightly to strongly roughened-tuberculate due to minute glandular hairs, youngest buds and nodal ridges often with a few unbranched to irregularly branched and matted multicellular hairs; internodes 1.8-5 cm long. Leaf blade 1-2 times as long as wide, 4.8-13.1 cm long, 3.8-9.1 cm wide, ovate or elliptic, less commonly obovate, coriaceous, often slightly curved abaxially; apex short-acuminate or acute to obtuse; base slightly cordate or rounded, less commonly slightly decurrent; margin usually slightly to strongly revolute, especially near base, appearing nearly entire, but actually obscurely serrate in distal ca 3/4; venation basal or slightly suprabasal, usually with 2 pairs of conspicuous secondary veins, the largest pair joining midvein 0-3 mm above lamina base, and 1 pair of less conspicuous, intramarginal secondary veins; adaxial surface with midvein, secondary veins, and tertiary veins slightly to strongly impressed in living material, often flattening upon drying; abaxial surface with midvein and largest pair of secondary veins raised, the intramarginal secondary veins and tertiary veins less raised, the quaternary veins very slightly raised, the higher order veins flat, the surface essentially glabrous, but with some scattered minute, glandular hairs; marsupiform domatia absent on abaxial surface in axils at junction of midvein and largest pair of secondary veins, persistent axillary hair tufts absent. Petiole 8-21 mm long. Inflorescences borne exclusively on old leafless nodes below leaves, 2.8-7.4 cm long, 1.5-4.5 cm wide, 1-2 branched; peduncle 6-25 mm long. Hypanthium 2.6-2.8 mm long, 2.3-2.8 mm wide, subglobose or urceolate, moderately pubescent with minute glandular hairs, the portion free from ovary 0.8-1.2 mm long; portion of calyx bearing external teeth 0.3-0.5 mm long. Calyx teeth ca 0.4 mm long, 0.4 mm wide. Calyptra present in bud, dome-like, with a caducous apiculum to ca 0.15 mm long. Petals 2.7-3.1 mm long, 2.4-3 mm wide, obovate, strongly cupped adaxially, red-purple, spreading; apex rounded, emarginate. Stamens red-purple with anther sacs whitish; filament narrowly ovate, ca 2.9 mm long, ca 0.8 mm wide; anther narrowly obovate, ca 2.8 mm long, 0.8 mm wide, the anther sacs whitish, ca 0.9 mm long, opening by 2 apical-lateral slits, septum intact. Ovary ca 3/4 to fully inferior, 1.8-2.2 mm long, 1.5-2.1 mm wide, the apical appendage 0.5-0.8 mm high; style ca 5.3 mm long, 0.6 mm wide, red-purple, straight or slightly curved; stigma ca 0.6 mm wide. Berries ca 9 mm in diameter; seeds 0.8-1 mm long, 0.4-0.5 mm wide. Figs. 47A-E, 48.

    Habitat and Distribution: South island Hispaniola and eastern Cuba: found in broad-leaved cloud forests of the Massif de la Selle and Massif de la Hotte of Haiti (1200-2225 m), and in the Cordillera del Turquino of Cuba (700-1000 m). See Judd (1987) for a discussion of the best remaining forests of these areas in Haiti, and Borhidi & Muñiz (1986), Seifriz (1943), and Smith (1954) for general accounts of forests in the Sierra Maestra. (Fig. 49).

    Phenology: Known to flower from November through February, and to produce mature fruit in July and August.

    Taxonomy and Systematics: Mecranium tuberculatum is very similar to M. haemanthum. Both species have strongly quadrangular stems, cauliflorous flowers with red-purple petals, and anthers that open by two slits. Mecranium tuberculatum differs from M. haemanthum in having stems that are usually conspicuously roughened, and leaves that are proportionally shorter and broader (1-2 times as long as wide vs. 2-3.5 times as long as wide). The leaves of M. tuberculatum have apices that are short-acuminate to obtuse, while those of M. haemanthum are usually acuminate. In fresh material, the leaves of M. tuberculatum have their major veins impressed above, while those of M. haemanthum are flat to slightly impressed. Plants of M. tuberculatum from high elevations of the Massif de la Hotte tend to have smaller leaves than those from lower elevation populations in the Massif de la Selle and Sierra Maestra. The specific epithet refers to the roughened-tuberculate young stems commonly found in this species.

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