Miconia subcompressa (Urb.) subsp. subcompressa

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, near Aux Cayes, ca 800 m alt., fl, 11 Jun 1917, E. L. Ekman H206 (holotype: S!).

Description: Shrub or small tree to ca 5 m tall. Indumentum of multicellular, ferrugineous, stellate-branched hairs. Young twigs not ridged, ± elliptic, 4-9.5 (-11) mm wide, sulcate, becoming terete with age, the indumentum usually dense, stellate to elongate-stellate or globular-stellate, ± glabrescent; internodes 1-7.5 (-9) mm long. Leaves with petiole 1-5 cm long, the indumentum dense; blade 8-31.5 cm long, 2.7-12 (-15.7) cm wide, ovate to occasionally elliptic or elliptic-oblong, flat, coriaceous, the apex slightly to clearly acuminate, the base (acute) obtuse to slightly cordate, the margin plane, usually clearly and irregularly serrate, the largest teeth (0.3-) 0.4-4 mm long, becoming entire near base, 3-33% of margin entire; venation acrodromous, slightly suprabasal, with midvein and 4 or 6 secondary veins, with 2 conspicuous secondary veins placed 3-20 (-27) mm in from margin and 4 or less commonly 2 inconspicuous 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 dark green, the indumentum dense when young, quickly glabrescent, the midvein and major secondary veins impressed, minor secondary, tertiary veins (and higher order veins) slightly impressed, the surface minutely papillose when dry due to numerous druse crystals; abaxial surface ferrugineous, very light golden to dark reddish-brown, densely (moderately) covered with multicellular, stellate hairs to ca 0.8 mm across, the midvein and major secondary veins prominently raised, minor secondary, tertiary, and quaternary veins raised, the higher order veins slightly to not at all raised. Inflorescences many-flowered, open, paniculate cymes of usually 3 to 5 major branch-pairs, ca 3.5-15 cm long, 3.5-12 cm across; proximal segment of lowermost inflorescence branches 1-4.7 cm long, distal internodes increasingly shorter, the ultimate branches (1.5-) 2-6 mm long, all with dense pale to deeply ferrugineous stellate indumentum; peduncle 3-10.5 cm long; each inflorescence branch associated with an early caducous, broadly elliptic to narrowly ovate bract, 5.5-15 mm long, 1.5-2.5 mm wide, the apices acute; flowers in dichasia, each flower associated with a pair of caducous, narrowly elliptic to ovate or linear bracteoles, ca 2-6 mm long, 0.5-1 mm wide, the indumentum dense, their apices acute to obtuse. Flowers with pedicel 0.4-1.3 mm long. Hypanthium ± cylindrical, free portion ca 1.7-2.2 mm long, the outer surface with moderate to dense, ferrugineous, stellate to globular-stellate hairs, the inner surface glabrous and 10-ridged, the apices of the ridges forming minute projections ca 0.1 mm long. External calyx lobes 5, 0.4-3 mm long, 0.9-1.5 mm wide, broadly to narrowly triangular with acute to acuminate apex, dense ferrugineous ± stellate indumentum; internal calyx lobes 5, ca 1.2-3.3 mm long, 2.3-3 mm wide, broadly ovate-triangular, green, green with red tinge, or reddish, with sparse to dense ferrugineous indumentum on both surfaces, the apex rounded (obtuse to acute), the margin minutely erose; calyx tube 0.3-0.8 mm long. Petals 5, 3.8-6.3 mm long, 2.8-4.8 mm wide, broadly ovate to elliptic or obovate, glabrous, white; margin entire. Stamens 10, geniculate; proximal segment 1.3-2.9 mm long; distal segment 2.6-4.2 mm long, with minute dorsal projection, the anther ca 1.8-3.2 mm long, with fertile portion of anther sacs ca 1.6-2.8 mm long, the connective/distal part of filament extending 1.6-2.8 mm beyond the base of anther sacs. Ovary 5-loculate, ± half-inferior, 2.2-3.4 mm long, 2.9-4.5 mm in diameter, short-ovoid, glabrous and 10-ridged, with minute apical projections, to ca 0.4 mm long, encircling base of style; style 3.3-4.8 mm long, glabrous; stigma truncate. Mature berries ca 8-11 mm in diameter, globose, blue (red when immature), moderately to sparsely covered with globular-stellate hairs. Seeds 0.5-0.8 mm long, angular-obovoid; testa smooth. Figs. 63-65.

Habitat and Distribution: Hispaniola (Haiti and the Dominican Republic), Massif de la Hotte and Massif de la Selle/Sierra de Baoruco, and thus is limited to the southern portion of the island; cloud forests, moist forests on limestone, and moist forests of Pinus occidentalis; 700 to 1800 m. Associated melastomes include Calycogonium torbecianum, Clidemia umbellata, Conostegia icosandra, Henriettea barkeri, Mecranium birimosum, M. haitiense, M. microdictyum, M. ovatum Cogn., M. revolutum, M. tricostatum, Meriania brevipedunculata, Meriania involucrata, Miconia alainii, M. barkeri, M. calycina, M. favosa, M. ferruginea, M. howardiana, M. hypiodes, M. laevigata, M. mirabilis, M. ossaeifolia, M. prasina, M. tetrastoma, M. xenotricha, Leandra lima, L. limoides, Sagraea setulosa, S. woodsii, and Tibouchina longifolia. Detailed lists of associates in the moist forests of Pinus occidentalis, cloud forests, and moist forests on limestone in the Massif de la Hotte and Massif de la Selle are given by Judd (1987) and Judd et al. (1990, 1998); see also Holdridge (1947).

Phenology: Flowering throughout the year.

Taxonomy and Systematics: Miconia subcompressa is probably most closely related to M. septentrionalis, M. jimenezii, M. hypiodes, and M. rufa. This putative monophyletic group, here called the densely-stellate clade, is present in the majority of the most parsimonious trees generated on the basis of morphological data (see phylogenetic analyses), but in some trees M. hypiodes is placed elsewhere, and in a few a M. subcompressa + M. hypiodes clade is placed, instead, sister to the bullate-leaved clade (i.e., M. sintenisii and relatives). The monophyly of a clade containing Miconia subcompressa, M. septentrionalis, M. jimenezii, M. hypiodes, and M. rufa is weakly supported by the synapomorphies of the abaxial surface of the leaves densely covered (on veins and lamina) with ferrugineous, stellate-branched hairs, and large berries. This putative clade also has quite large flowers (see also Judd & Beaman 1988). Miconia subcompressa possibly is sister to M. hypiodes, and may be differentiated from it by the leaf blades usually 7.5-26 cm long (vs. 1.5-6 cm long) and with slightly to distinctly acuminate apices (vs. rounded to acute apices), flowers with the hypanthium 1.2-2.5 mm long and with less conspicuous and more regularly spaced marginal teeth on the inner surface, and the ovary 5-locular (vs. 3-locular). Miconia subcompressa also has more prominently serrate leaves with often six secondary veins, larger inflorescences with longer pedicels and larger bracts, and flowers with often longer external calyx lobes (see Judd & Beaman 1988). The two species usually do not occur together because M. subcompressa is most common below 1800 m and M. hypiodes is most common at or above 1900 m elev. Miconia subcompressa has previously been circumscribed more broadly to include plants here considered as M. septentrionalis and M. jimenezii, two likely closely related species. It is easily distinguished from these two species by its non-ridged twigs, and leaves with the tertiary veins of the lamina jointed by percurrent-orthogonal quaternary veins (see key; Judd & Beaman 1988). These two species occur in various mountains of northern Hispaniola, while M. subcompressa is restricted to southern Hispaniola, occurring in the Massif de la Hotte and Massif de la Selle/Sierra de Baoruco. Finally, M. subcompressa differs from M. rufa in that the hairs of the midvein of the abaxial leaf surface are mostly stellate to globular-stellate (vs. with numerous elongate-branched hairs intergrading with stellate and globular-stellate hairs), and because the inner surface of its hypanthia have ten regular to irregular ridges (vs. with ten major and ten minor ridges). The two are geographically isolated; M. rufa is restricted to mountains of eastern Cuba.

Taxonomy and Systematics (cont.): Plants from higher elevations in the Massif de la Hotte and Massif de la Selle usually have smaller leaves with less conspicuous teeth and an indumentum of dark reddish-brown (vs. light golden to moderately ferrugineous) stellate hairs. However, field and herbarium investigations indicate complete intergradation between these forms and plants of lower elevations. Thus, Miconia plumerii (based on material collected above 1600 m alt. on Morne Formon; see Urban and Ekman 1929; Judd & Beaman 1988) is considered conspecific with M. subcompressa. The specific epithet “plumerii” in Miconia plumerii is likely a typographic error, with Urban and Ekman intending the spelling “plumieri” in honor of Charles Plumier (1646-1704). I am not aware of anyone named Plumer associated with West Indian botany and Urban and Ekman are unlikely to have made the mistake of adding the second “I" to the epithet. In addition, when the derivation of a new name was not obvious, Urban noted for whom the species was named. In this case he did not do so, probably because Plumier didn’t require an explanation. The Haitian common name is “Macreole.”

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