Miconia leptantha 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, Les Roseaux, Quillaud, ca 1500 m, very steep mtn slope near pines, fl, 27 Jun 1928, E. L. Ekman H10153 (holotype: S!).

Description: Shrub to ca 2 m tall. Indumentum of multicellular, pale ferrugineous, matted stellate-branched hairs, and minute globular hairs. Young twigs not ridged, ± rectangular in cross-section, 1.5-2.5 mm wide, becoming terete with age, the indumentum of sparse, pale ferrugineous, matted stellate-branched hairs, and scattered minute globular hairs, quickly glabrescent, even on young twigs with leaves; internodes 0.6-2.8 cm long. Leaves with petiole 3-10 mm long, the indumentum same as that of twigs; blade 3.1-11 cm long, 1.4-3.5 cm wide, slightly ovate to elliptic, flat, coriaceous, the apex acuminate, the base acute to obtuse, the margin plant to very slightly revolute, serrulate distally, ca 9-40% of margin entire, the largest teeth 0.25-0.3 mm long; venation acrodromous, ± basal, with prominent midvein and 2 conspicuous secondary veins placed ca 1.5-5 mm in from margin, with 2 inconspicuous secondary veins closer to margin, and numerous percurrent tertiary veins oriented subperpendicular to midvein, the higher order veins ± orthogonal-reticulate, usually a few quaternary veins slightly more prominent and obviously connecting the tertiary veins (percurrent); adaxial surface green, the indumentum of sparse appressed stellate-branched hairs and minute globular hairs, but very quickly glabrescent, the midvein and major secondary veins impressed, minor secondary veins, tertiary and higher order veins flat, the surface appearing ± minutely papillose after drying due to presence of numerous druse crystals; abaxial surface light green, ± glabrous or with very sparse minute globular hairs (sparse appressed stellate-branched hairs present on very young leaves, but such hairs very quickly caducous), the midvein and major secondary veins prominently raised, tertiary veins very slightly raised, higher order veins flat. Inflorescences many-flowered, open-paniculate cymes of 4 or 5 major branch pairs, 5-7 cm long, 2-2.8 cm across; proximal segment of lowermost inflorescence branches 5-9 mm long, distal internodes of inflorescence branches increasingly shorter, ultimate branches 0.5-2.5 mm, sparse minute globular hairs to ± glabrous; peduncle 1-2 cm long, with similar indumentum; each inflorescence branch associated with an early caducous, narrowly triangular-linear to elliptic bract, ca 2-3 mm long, 0.5-1.5 mm wide, the apices acute, the lowermost pair sometimes expanded and intergrading with leaves; flowers in dichasia and appearing as in 3-flowered glomerules, each subtended by 2 caducous, narrowly ovoid to triangular or linear bracteoles 0.6-1.5 mm long, 0.1-0.5 mm wide, the indumentum of sparse minute branched hairs and globular hairs, their apices acute. Flowers ± sessile. Hypanthium cylindrical, free portion ca 0.6-0.7 mm long, the outer surface with sparse branched hairs and minute globular hairs, the inner surface glabrous, not ridged. External calyx lobes 5, 0.2-0.4 mm long, 0.8-1 mm wide, broadly triangular, with acute to acuminate apex, indumentum of very sparse branched hairs and minute globular hairs; internal calyx lobes 5, 0.4-0.6 mm long, 0.7-1 mm wide, triangular, green, glabrous, the apex rounded to obtuse, the margin entire; calyx tube 0.1-0.2 mm long. Petals 5, ca 1.5-1.7 mm long, 0.8-1 mm wide, ovate to elliptic, glabrous, white; margin entire. Stamens 10, geniculate; proximal segment 1.1-1.6 mm long; distal segment 1.2-1.7 mm long, with minute dorsal projection, the anther ca 0.8-1.1 mm long, with fertile portion of anther sacs 0.7-1 mm long, the connective/distal part of filament extended 0.4-0.6 mm beyond the base of the anther sacs. Ovary 2-locular, 1/2 to 2/3-inferior (immature), 0.9-1.2 mm long, 1.2-1.4 mm in diameter, short-ovoid to subglobose, glabrous and obscurely ridged, with fluted apical projection to ca 0.1 mm encircling the base of style; style 1.7-2.4 mm long, glabrous; stigma truncate. Berries not seen, probably globose, ± glabrous.

Habitat and Distribution: Hispaniola (Haiti), Massif de la Hotte, Les Roseaux region, near Quillaud; steep slopes in pinelands; ca. 1500 m. It is only known from the type. It was likely collected with Henriettea barkeri, H. megaloclada (Urb. & Ekman) Alain, and Sagraea scalpta, based on Ekman’s field notes (xerographic copy in library at FLAS).

Phenology: Known only from a single flowering specimen collected in June.

Taxonomy and Systematics: Miconia leptantha probably is most closely related to M. ossaeifolia and M apiculata, and is compared with these species in the discussion under M. apiculata. It is most similar to M. ossaeifolia, which has similar minute flowers. It can be distinguished from M. ossaeifolia by the lack of conical projections on its adaxial leaf surface, the lack of ferrugineous stellate hairs on its abaxial leaf surface, the free portion of its hypanthium ca 0.6-0.7 mm long (vs. 0.7-1 mm long), stamens with the proximal segment 1.1-1.6 mm long (vs. 0.6-0.8 mm long), and 2-loculate (vs. 3 or 4-loculate) ovaries. In addition, it often has shorter petioles. All of these species are endemic to the Massif de la Hotte, Haiti, but neither is known to co-occur with M. leptantha. Miconia leptantha is known only from the type; it is unfortunate that it was not re-collected during several trips made by J. D. Skean, Jr. and myself to various localities in the higher elevations of the Massif de la Hotte.