Macairea

Authority

Renner, Susanne S. 1989. Systematic studies in the Melastomataceae Bellucia, Loreya and Macairea. Mem. New York Bot. Gard. 50: 1-112.

Family

Melastomataceae

Scientific Name

Macairea

Description

Species Description - Shrubs, 1-2 m tall, subshrubs, or rarely treelets (5-12 m tall); branchlets angled; bark longitudinally fissured, exfoliating in thin strips; indument on the young branchlets densely hirsute, sericeous, or lepidote (in M . linearis) with glandular or eglandular hairs, sometimes with globose sessile glands, rarely glabrous. Leaves opposite, elliptic, broadly ovate, obovate, cordate, or linear, petiolate, 3-9-nerved, the lateral pairs of primary veins arising at the blade base or up to 4 mm above the base, the outermost pair close to the margin and often inconspicuous (leaves may appear almost pinnately veined), subcoriaceous or thin and brittle, upper surface drying green, with stout, conical, glandular or eglandular hairs, or verrucose, or glabrous, lower surface rust-colored or pale green, hirsute or sericeous with glandular or eglandular hairs, sometimes with globose sessile glands, or with very short few-branched papillae-like hairs, or glabrous. Inflorescence a terminal, many-flowered elongate or congested paniculate cyme, or groups of 3-5 subsessile flowers in the axils of the uppermost leaves; peduncles hirsute or sericeous with glandular or eglandular hairs, sometimes with globose sessile glands, or lepidote; pedicels with bracts and bracteoles, indument usually ofthe same type as on the peduncle; bracts subpersistent, margin often hyaline and serrulate. Flowers hermaphroditic, 4-merous; hypanthium campanulate, terete or inconspicuously 8-ribbed, hirsute or sericeous with indument of the same type as the pedicel and bracts, or glabrous; calyx lobes narrowly to broadly triangular. spreading, persistent on the limb after anthesis; petals thin, obovate, apically sometimes emarginate, basally with a minute claw, basally white, turning red with age, apically orchid rose, pink, or magenta, or petals white, or purple, margins (at least in bud) with globose short-stalked glands; stamens eight, dimorphic or subisomorphic, of roughly the same length as the petals; filaments thin, terete, ventrally with globose short-stalked glands or glabrous; anthers linear, single-pored, rostrate, rarely truncate, connective prolonged and expanded dorsi-basally into a cordate or collar-like appendage often surrounding the insertion of the filament; ovary free, perigynous, 2-4-locular, apically with glandular or rarely eglandular hairs; style thin, terete or subclavate (M. lasiophylla), sigmoid, in the mid-section with short glandular hairs, longer than the stamens and exserted from the corolla; stigma punctiform. Fruit a loculicidal, many-seeded, dark brown capsule. Seeds 0.5-1.4 mm long, cochleate or polyhedric, testa tuberculate or reticulatefoveate.

Discussion

Type: Macairea radula (Bonpl.) De Candolle. Rhexia radula Bonpland in Humboldt & Bonpland, Monogr. Melast. 2: 107, pL 41. 1820.

Siphantheropsis Brade, Inst. Nac. Pesq. Amazonia Bot. 8: 4. 1958. Type: Siphantheropsis williamii Brade.

Distribution

A neotropical genus of 22 species, ranging from the Guyana Highlands through Venezuelan and Brazilian Amazonia to central Brazil and northe m Bolivia and west into Colombia and Peru; savannas in lowlands and on the Guayana sandstone mountains to 2500 m.