Mecranium haemanthum Triana ex Cogn.

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Mecranium haemanthum Triana ex Cogn.

  • Primary Citation

    Monogr. Phan. 7: 983. 1891

  • 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: CUBA. [Guantánamo]: Pinal de St. Ana, 800 m, fl, fr, Apr 1889, Eggers 5176 (lectotype: designated by Skean, 1993, M!; isolectotypes: A! BR! GOET! US!).

    Description: Shrub or small tree to ca 6 m tall. Twigs strongly 4-angled and ridged, 2-4 mm in diameter, essentially glabrous or sometimes appearing slightly scurfy due to minute glandular hairs, youngest buds and nodal ridges usually with a few unbranched to irregularly branched and matted multicellular hairs; internodes 1.5-4.8 cm long. Leaf blade 2-3.5 times as long as wide, 6.6-20.6 cm long, 2.5-8.4 cm wide, ovate or elliptic, coriaceous; apex acuminate, less commonly acute; base rounded or slightly cordate; margin usually slightly to strongly revolute, 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 0.5-6 mm above lamina base, and 1 pair of less conspicuous, intramarginal secondary veins; adaxial surface with midvein, secondary veins, and tertiary veins flat or slightly impressed; abaxial surface with midvein and largest pair of secondary veins raised, the intramarginal secondary veins and tertiary veins less raised, the quaternary veins flat or very slightly raised, the smallest veinlets flat, the surface with scattered minute glandular hairs, often concentrated on veins; marsupiform domatia absent on abaxial surface in axils at junction of midvein and largest pair of secondary veins, persistent axillary hair tufts absent. Petiole 10-41 mm long, essentially glabrous. Inflorescences borne exclusively on leafless nodes below leaves, 1.4-5 cm long, 0.9-4.3 cm wide, 1-2 branched; peduncle 4-11 mm long. Hypanthium ca 3.3 mm long, 2.7-3.2 mm wide, subglobose or urceolate, slightly pubescent with minute glandular hairs, the portion free from ovary 1-1.2 mm long; portion of calyx bearing external teeth 0.3-0.5 mm long. Calyx teeth ca 0.3 mm long, 0.3 mm wide. Calyptra present in bud, dome-like, with a caducous apiculum to ca 0.15 mm long. Petals 2.9-3.3 mm long, 2.7-3.6 mm wide, obovate, strongly cupped adaxially, red-purple, spreading; apex rounded, emarginate. Stamens red-purple, with anther sacs whitish; filament elliptic or narrowly ovate 3.2-3.4 mm long, ca 0.8 mm wide; anther narrowly obovate, 2.9-3.5 mm long, 0.6-0.8 mm wide, the anther sacs 0.9-1.3 mm long, opening by two apical-lateral slits, the septum intact. Ovary 3/4 to fully inferior, ca 2.3 mm long, 2.2-2.6 mm wide, the apical appendage 1-1.3 mm high; style 5.8-6.3 mm long, ca 0.6 mm wide, red-purple, straight or slightly curved; stigma 0.5-0.7 mm wide. Berries and seeds not seen. Fig. 47F-H.

    Habitat and Distribution: Cuba: moist thickets, broad-leaved forests on limestone, and broad-leaved cloud forests in the Cordillera de Guaniguanico, Cordillera del Turquino, Cuchillas de Baracoa, Cuchillas de Toa, Meseta del Guaso, Sierra del Cristal, Sierra de Imías, and Sierra del Purial, especially along streams. A single population is known from Loma de la Coca in the Alturas de la Habana Matanzas; (200-) 500-1300 m. (Fig. 24).

    Phenology: Known to flower from November to June, with peak flowering December through March.

    Taxonomy and Systematics: Mecranium haemanthum is a cauliflorous Cuban species with red-purple flowers and anthers that open by means of two slits. It is very similar to M. tuberculatum, a species of the Cordillera del Turquino of eastern Cuba and south island Hispaniola. See Key and Appendix 2 for characteristics separating the two species. Mecranium haemanthum exhibits a discontinuous distribution, occurring in the mountains of La Habana and Pinar del Río provinces in the west, and in the mountains of Gramna, Guantánamo, Holguín, and Santiago de Cuba provinces in the east. Having a relatively broad geographical and elevational distribution, it is not surprising that M. haemanthum exhibits a great deal of morphological variation in the characters of leaf size and shape. Plants from populations on western Cuba tend to have longer leaves with more acuminate apices than plants from populations on the eastern part of the island. See Alain (1957, p. 43) for a photograph of a plant from western Cuba. Mecranium haemanthum was confused by earlier botanists with M. virgatum, a cauliflorous Jamaican endemic. Plants of the two species may have similar leaves, but M. virgatum has white flowers with stamens that open by a gaping foramen, and twigs that are moderately 4-angled, lacking the conspicuous longitudinal ridges of M. haemanthum. Grisebach (1866) cited the collection Wright 1218 (M. haemanthum) under the name Cremanium virgatum. Charles Wright (1869) corrected Grisebach's error and gave the Cuban plants the name Mecranium coccineum, a nomen nudum. Triana (1871) coined the name Mecranium haemanthum for these plants, presumably for their red-purple flowers, but like Wright, failed to present a description. Later, the species name was published validly by Cogniaux (1891), who cited the collections Wright 1218 and Eggers 5176 as syntypes. I have chosen a sheet of Eggers 5176 at M as the lectotype for this species in order to avoid the confusion surrounding the "mixed collections" of Charles Wright that were distributed under a single number by Asa Gray (see discussion under M. obtusifolium). In the case of M. haemanthum, Wright 1218 represents four different collections, including populations from both eastern and western Cuba. I have listed these in the specimen citations as "Wright Collections" because of the difficulty in determining the geographical origin of each specimen.

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