Miconia xenotricha Urb. & Ekman

Description

Description Author and Date: Walter S. Judd, 2010, based on Judd, W. S. (2007). Revision of Miconia sect. Chaenopleura (Melastomataceae) in the Greater Antilles. Systematic Botany Monographs 81:1-235.

Type: HAITI. [Dept. du Sud]: Massif de la Hotte, western group, near Torbec, Morne Formon, bottom of ravine, 1400 m elev., fl, 28 Dec 1926, E. L. Ekman H7447 (holotype: S!; isotypes: NY!, S!, US!).

Description: Shrub or small tree to ca 3.5 m tall. Indumentum of multicellular, pale ferrugineous, stout-stalked dendritic to ± conical and poorly branched, or slightly smaller, ± globular-stellate hairs, and minute globular hairs. Young twigs not ridged, ± rectangular in cross-section, 4.5-8 mm wide, becoming terete with age, the indumentum of sparse to moderate, pale ferrugineous, stout-stalked shortly and irregularly branched conical, to globular, or globular-stellate hairs, and scattered minute globular hairs; internodes 2.5-15.5 cm long. Leaves with petiole 1.7-3.5 cm long, the indumentum moderate to dense and similar to that of stems; blade 12-24.2 cm long, 7-13.3 cm wide, ovate to elliptic, flat, coriaceous, the apex acute to acuminate, the base cordate, the margin plane, ± serrulate to irregularly serrate to base, ca 0% of margin entire, the largest teeth 0.3-2.7 mm long, not associated with a long-stalked hairs; venation acrodromous, ± basal, with prominent midvein and 4 or 6 secondary veins, with 2 conspicuous secondary veins placed 10-29 mm in from margin, with 4 less conspicuous secondary veins closer to margin, and numerous percurrent tertiary veins oriented subperpendicular to midvein, the tertiary veins joined by percurrent-orthogonal quaternary veins; adaxial surface green (sometimes yellowish after drying), the indumentum initially of moderate, stout-stalked, ± dendritic hairs and minute-globular hairs but quickly glabrescent except for a few hairs along basal portion of midvein, the midvein and secondary veins clearly impressed, tertiary and quaternary veins also impressed, thus delimiting ± raised, areoles, especially toward margin, i.e., surface ± bullate but sometimes obscured in dried material by pressing, the lamina surface not associated with thick-based hairs as in M. campanensis, and minutely papillose after drying due to presence of numerous druse crystals; abaxial surface light green, sparsely to moderately covered with pale ferrugineous, stout-stalked, dendritic to smaller globular-stellate hairs and scattered minute globular hairs on midvein to highest order veins, but globular-stellate hairs more frequent on tertiary, quaternary, and higher order veins, all hairs ± persistent, those on midvein and secondary veins 0.3-1 mm long/across, those on higher order veins 0.3-0.7 mm across, the midvein and major secondary veins prominently raised, minor secondary and tertiary veins raised, quaternary veins slightly raised, higher order veins very slightly raised to flat. Inflorescences many-flowered, broadly rounded (to broadly paniculate) cymes of 2 or 3 major branch-pairs, 5.5-10 cm long, 4-10 cm across; proximal segment of lowermost inflorescence branches 2-3.4 cm long, distal internodes shorter, ultimate branches 1.6-8.1 mm long, sparse to moderate, pale ferrugineous, stout-stalked dendritic to globular-stellate, with scattered minute globular hairs; peduncle 6.5-17.5 cm long, with similar indumentum; each inflorescence branch associated with early caducous, narrowly ovate to obovate bract, 9-25 mm long, 2.8-3 mm wide, the apices acute to rounded; flowers in dichasia, each subtended by 2 caducous, ± linear to obovate bracteoles, 5-10.9 mm long, 1.5-3.4 mm wide, the indumentum of sparse to moderate stellate hairs, their apices acute to rounded. Flowers sessile or nearly so; pedicel 0.5-1.4 mm long. Hypanthium cylindrical, free portion 1.4-1.9 mm long, the outer surface with sparse, pale ferrugineous, stellate hairs and minute globular hairs, the inner surface glabrous and clearly ridged, the apices of the ridges slightly projecting, to ca 0.1 mm. External calyx lobes 5, 0.7-0.9 mm long, 1.4-1.8 mm wide, broadly triangular, with apex acuminate, indumentum of very sparse stellate hairs and minute globular hairs; internal calyx lobes 5, 0.9-1.6 mm long, 1.5-2 mm wide, broadly ovate-triangular, green, ± glabrous, the apex acute to rounded, the margin minutely dentate; calyx tube nearly absent. Petals 5, 2.2-3.5 mm long, 3-4 mm wide, broadly ovate to elliptic, glabrous, pale green; margin entire to minutely erose. Stamens 10, geniculate; proximal segment 1.1-1.5 mm long; distal segment 2.6-2.8 mm, with minute dorsal projection, the anther 1.9-2.4 mm long, with fertile portion of anther sacs 1.6-2 mm long, the connective/distal part of filament extended 0.5-0.6 mm beyond the base of the anther. Ovary 4- or 5-loculate, ca 2/3-inferior, 1.7-2.5 mm long, 2.1-3 mm in diameter, short-ovoid, glabrous and obscurely ridged, with apical projections to 0.1 mm encircling base of style; style ca 2-2.5 mm [immature] long, glabrous; stigma truncate. Berries 7.4-8.6 mm long, 6.4-7.7 mm in diameter, ± globose, pale gray-blue, with sparse stellate hairs, minute globular hairs. Seeds 0.45-0.7 mm long, angular-obovoid; testa ± smooth. Figs. 84, 88.

Habitat and Distribution: Hispaniola (Haiti), Massif de la Hotte; cloud forest and moist forest of Pinus occidentalis; 1400-1950 m. Associated melastomes include Clidemia umbellata, Mecranium birimosum, M. microdictyum, M. revolutum, Miconia barkeri, M. hypiodes, M. subcompressa, and M. tetrastoma. The high montane forests of the Massif de la Hotte are described in detail in Judd (1987) and Judd et al. (1990, 1998).

Phenology: Flowering period poorly known; flowering material collected in June and December.

Taxonomy and Systematics: Miconia xenotricha, a member of the bullate-leaved clade (see discussion under M. foveolata, and phylogenetic analyses), is likely most closely related to M. favosa (see discussion under that species). Both lack long-stalked hairs on the adaxial surface of their leaf blades. The characters most useful in distinguishing M. xenotricha from M. favosa are listed in the key (see also Judd et al. 1995). As discussed under M. favosa, the two are geographically isolated. Miconia xenotricha is one of a number of distinctive endemics to the high elevation forests of the Massif de la Hotte. The pattern of variation within this species, which was until recently only known from the type, has been clarified by the recent collections of Judd and Skean, which were made in connection with a biological inventory of the Parc National Pic Macaya/Macaya Biosphere Reserve (Haiti) and taxonomic studies focused on the systematics of the Miconieae.

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v-249-01165604.jpg (image/jpeg)

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Botanical line drawing of Miconia howardiana, Miconia favosa, and Miconia xenotricha (image/jpeg)