Miconia rigida (Sw.) Triana

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Miconia rigida (Sw.) Triana

  • Primary Citation

    Trans. Linn. Soc. London 28: 130. 1871

  • Basionym

    Melastoma rigidum Sw.

  • 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: JAMAICA. [Blue Mtns], exact locality not specified, O. Swartz s.n. (holotype, S!; isotype: B-W, xerographic copy of specimen seen).

    Description: Shrub or small tree to 6 m tall. Indumentum of multicellular, reddish ferrugineous, elongate-branched, irregularly stellate-branched, to minute globular hairs, sometimes also with long-stalked, gland-headed hairs. Young twigs not ridged, ± elliptic or constricted-elliptic in cross-section, 2.5-6 mm wide, becoming terete with age, the indumentum of dense, elongate-branched, irregularly stellate-branched, to minute globular hairs, sometimes also with scattered long-stalked, gland-headed hairs, to 0.3-0.5 mm long, especially just above nodes; internodes 1.3-5.7 cm long. Leaves with petiole 0.7-6 cm long, the indumentum similar to that of twigs; blade 4.5-16 cm long, 2.8-9 cm wide, ovate to elliptic, ± flat, coriaceous, the apex acuminate to acute or obtuse, the base rounded to cordate, the margin plane to revolute, obscurely serrulate, proximal ca 0-27% of margin entire, the largest teeth 0.1-0.3 mm long, sometimes associated with long-stalked, gland-headed hair to 0.6-1.2 mm long; venation acrodromous, ± basal, with prominent midvein and 4 secondary veins, with 2 conspicuous secondary veins placed 3.5-16 mm in from margin, 2 inconspicuous secondary veins closer to margin, and numerous percurrent tertiary veins oriented subperpendicular to midvein, the tertiary veins ± connected by quaternary veins, and the higher order veins ± orthogonal-reticulate; adaxial surface green, initially with scattered hairs but very quickly glabrescent, the midvein and major secondary veins impressed, minor secondary and tertiary veins very slightly impressed to flat, higher order veins flat, the surface appearing slightly wrinkled when dry, with scattered druse crystals; abaxial surface green, sparsely to moderately covered with a mixture of irregularly stellate-branched to minute globular hairs or with mainly minute globular hairs on lamina and higher order veins, and such hairs moderate to dense on major veins, the hairs of higher order veins to 0.05-0.2 mm and those of midvein and secondary veins to 0.15-0.4 mm, elongate-branched hairs and long-stalked, gland-headed hairs sometimes also present on midvein, the primary and major secondary veins prominently raised, minor secondary veins and tertiary veins slightly raised, and higher order veins flat.

    Description (cont.): Inflorescences many-flowered, open paniculate cymes of 2 to 5 branch-pairs, 4.2-18.5 cm long, 3.5-15 cm across; proximal segment of lowermost inflorescence branches 1.2-4 cm long, distal internodes of branches shorter, ultimate branches 5-14 mm long, and flowers, thus, well separated from each other, with dense elongate-branched, irregularly stellate-branched, to minute globular hairs, often also with scattered long-stalked, gland-headed hairs; peduncle 2-7.4 cm long, with similar indumentum; each inflorescence branch associated with quickly caducous, narrowly ovate-triangular to ± linear bract, 4.3-9 mm long, 0.9-2.9 mm wide, the apices acute, the lowermost pair sometimes leaf-like; flowers in dichasia, well separated from each other, each subtended by 2 caducous, narrowly ovate-triangular to linear bracteoles, 3-6.2 mm long, 0.9-1.5 mm wide, the indumentum of irregularly stellate hairs, their apices acute. Flowers subsessile; pedicel 0.5-2 mm long. Hypanthium cylindrical, free portion 2.2-2.9 mm long, the outer surface with dense irregularly stellate-branched to minute globular hairs and sparse to dense long-stalked, gland-headed hairs, the inner surface glabrous or with a few stalked, gland-headed hairs near apex and slightly 20-ridged, the apices of the ridges not projecting, or some with apical projection to 0.1 mm. External calyx lobes 5, 0.2-0.7 mm long, 1.9-3.3 mm wide, triangular or broadly so, to nearly obsolete, with obtuse to acute apex, indumentum similar to hypanthium; internal calyx lobes 5, 0.8-1.3 mm long, 1.9-3.3 mm wide, ovate-triangular, green to red-tinged, with a few branched hairs, the apex rounded, the margin entire and fringed with branched hairs; calyx tube 0.2-0.4 mm long. Petals 5, 4.8-6.7 mm long, 3.8-5.2 mm wide, obovate, elliptic, to suborbicular, glabrous, white, sometimes pink-tinged abaxially; margin entire. Stamens 10, geniculate; proximal segment 2.7-3.2 mm long, distal segment 3.4-4.4 mm long, with minute dorsal projection, the anther 2.4-3.2 mm long, with fertile portion of anther sacs 1.3-1.7 mm, the connective/distal part of filament extended 0.9-1.6 mm beyond the base of the anther sacs. Ovary 3-loculate, ca 1/2-2/3-inferior, 3.8-5.7 mm long, 2.8-4.8 mm in diameter, ellipsoid to obovoid, apically glabrous or with a very few stalked, gland-headed hairs, and slightly to clearly ridged, with slightly lobed projection to 0.2-0.3 mm encircling the base of style; style 4.2-5 mm long, glabrous or with a few short- to long-stalked, gland-headed hairs, these occasionally with a few non-glandular branches; stigma truncate. Berries 5-8 mm long, 5-8 mm in diameter, globose to ± ellipsoid, red when slightly immature and turning blue at maturity, indumentum as hypanthium. Seeds 0.6-1.0 mm long, angular-obovoid; testa ± smooth. Fig. 58.

    Habitat and Distribution: Jamaica, Blue Mountains; in moist montane to cloud forests; 1250-2250 m. Associated melastomes include Conostegia montana, Mecranium purpurascens, Meriania leucantha, M. purpurea, Miconia dodecandra, M. quadrangularis, M. rubens, and M. tetrandra. These montane forests are described in more detail by Shreve (1914), Grubb and Tanner (1976), and Tanner (1977, 1986).

    Phenology: Flowering throughout the year.

    Taxonomy and Systematics: Miconia rigida, a member of the lax-inflorescence clade (see discussion under M. ferruginea) is likely most closely related to M. pseudorigida. Both species have cordate-based leaves and only distally fertile anthers, i.e., fertile region 1.3-1.7 mm long and anthers, themselves, 2.3-3.2 mm long). Miconia rigida is readily distinguished from M. pseudorigida by its stems that are densely covered with ferrugineous, elongate-branched to irregularly stellate-branched hairs, which occur with minute globular hairs and sometimes with scattered long-stalked, gland-headed hairs. The stems of M. pseudorigida, in contrast, are glabrous or only have scattered minute globular hairs, except for a band of long-stalked gland-headed or non-glandular multicellular hairs, often reddish, position just above each node. The external hypanthium surface of M. rigida is densely covered by irregularly stellate to minute globular hairs (and also has at least a few, and often numerous long-stalked gland-headed hairs), while the hypanthium of M. pseudorigida is nearly glabrous (aside from the few long-stalked, gland-headed hairs), i.e., it has only a sparse covering of minute globular to inconspicuous, matted, and irregularly branched hairs. Both are endemic to Jamaica, but M. rigida is limited to the Blue Mountains, where it grows from 1250-2250 m elev. in acidic soils, while M. pseudorigida is restricted to the John Crow Mountains, near Ecclesdown, where it occurs from 450-750 m elev. over limestone. Miconia rigida may also be related to the Hispaniolan species, M. adenocalyx, which also has cordate-based leaves with numerous lignified idioblasts in the petioles, and from which it may be distinguished by the characters listed under the treatment of that species (see above).

  • Sorry, no descriptions available for this record.