Mecranium plicatum Urb.

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Mecranium plicatum Urb.

  • Primary Citation

    Ark. Bot. 17(7): 47. 1921

  • 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 Hotte, near Belle Endroit, on a dry grassy slope (savanna), young fr, 9 Aug 1917, Ekman H658 (holotype: S!; isotype: K!).

    Description: Shrub or small tree of unknown height. Twigs moderately 4-angled, 1-2 mm in diameter, smooth, moderately pubescent with light brown, irregularly branched and matted to dendritic-stellate multicellular hairs; internodes 0.5-1 cm long. Leaf blade 2.9-6.3 cm long, 1.6-2.8 cm wide, ovate, membranaceous or coriaceous, often plicate if plant in full sun; apex acuminate; base rounded; margin often slightly revolute, especially near base, serrate in distal ca 3/4, the teeth ca 0.5 mm high, spaced 2-3 mm apart; venation basal or suprabasal, usually with 1 pair of conspicuous secondary veins joining midvein 0.5-4 mm above lamina base, and 1 pair of inconspicuous, intramarginal secondary veins; adaxial surface with midvein and largest pair of secondary veins flat or slightly impressed, the intramarginal secondary veins and tertiary veins flat or not visible; abaxial surface with midvein and largest pair of secondary veins raised, the intramarginal secondary veins and tertiary veins flat or very slightly raised, the quaternary and higher order veins flat, the surface with scattered minute glandular hairs and some irregularly branched to dendritic-stellate multicellular hairs near base; marsupiform domatia absent on abaxial surface in axils at junction of midvein and largest pair of secondary veins, persistent axillary hair tufts absent. Petiole 5-13 mm long, pubescent with hairs similar to those on stem. Inflorescences probably borne both in leaf axils and on leafless nodes below leaves, 1.8-2.5 cm long, 0.4-1.4 cm wide, 1-branched; peduncle 7-14 mm long. Flowers not known. Berries ca 5 mm in diameter, purple-black, glabrous or with a few minute glandular hairs, bearing calyx teeth ca 0.25 mm long, 0.4 mm wide, and an erose-ciliate toral fringe ca 0.3 mm high; seeds ca 0.5 mm long, 0.3 mm wide. Fig. 39.

    Habitat and Distribution: Hispaniola: endemic to the Massif de la Hotte of Haiti; elevation unknown. (Fig. 38).

    Phenology: Essentially unknown. A single collection bearing immature fruits was made in August.

    Taxonomy and Systematics: Mecranium plicatum is known only from the type collection, which was made in the region of Morne Vanderveld (see Skean 1989a). Since the flowers of M. plicatum remain unknown, no attempt has been made to include this species in the cladistic analysis or general key. However, the species is included in Appendix 1, the key to Hispaniolan species. The presence of true axillary inflorescences, 4-merous fruits, and a toral fringe confirm the placement of this species in Mecranium. Mecranium plicatum is unique among all other species of the genus in having branched hairs that are nearly dendritic-stellate. With relatively large immature fruits and membranaceous to coriaceous, plicate leaves, plants of this species are similar to M. acuminatum and M. amygdalinum. They are also similar to M. microdictyum, except for their apparently larger flowers. Mecranium plicatum has occasionally been confused with M. amygdalinum. The latter generally has narrower leaves (1.1-2.3 vs. 1.6-2.8 mm wide), is much less pubescent, and is not known from the Massif de la Hotte.

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