Tococa obovata Gleason

Description

Description Author and Date: Fabian A. Michelangeli, January 2010, based on Michelangeli, F. A. (2005). Tococa (Melastomataceae). Flora Neotropica Monographs 98: 1-114.

Type: Venezuela. Amazonas: Mount Duida, 1450 m, 5 JAN 1929, Tate 593 (holotype NY).

Description: Shrub, to 0.3-2.0 m tall. Stems with a mix of glandular and non-glandular setae 3-7 mm long, persistent, the nodes glabrous. Petioles 0.3-0.9 (-1.8) cm long, with a mix of glandular setae and lepidote hairs. Leaves isophyllous, elliptic-ovate to oblong, occasionally obovate, 4.0-8.5 x (1.5-) 2.0-5.0 cm, apex acute to round, base round to cordulate, the sinus up to 6 mm long, adaxial surface adpressed-setose, abaxial surface sparsely glandular setose to furfuraceous on the veins, but the surface in between glabrous, light green, with 2 pairs of secondary veins, basally nervate, coriaceous, entire, ciliate; domatia rarely present (only in T. obovata subsp. neblinensis). Inflorescence terminal, solitary or a panicle of 3-5 flowers, 2-5 cm long, the axis green, terete. Flowers on pedicels 5-10 mm long, articulated at the base of the hypanthium flared at the apex, subtended by persistent bracts, subulate but with a broad base, 1.5-2.0 x 0.6 mm; hypanthium campanulate, 7.5-8.0 mm long, sparsely glandular pubescent, and with short lepidote trichomes; sepals broadly triangular, fused at the base 0.7-1.5 mm, 2.5-3.0 mm long, calyx teeth narrowly triangular, projecting above the sepals 1.5-2.5 mm long, glandular setose; the ring inside the torus glabrous. Petals 5, obovate-oblong, 15-22 x 7-10 mm, base attenuate, emarginated, smooth, glabrous, occasionally with a caducous terminal glandular setae, in bud the exposed surface of the petal red, the remaining surface white, the adaxial surface pink. Stamens all of the same size, the filaments 8.0-9.0 mm long, glabrous; anthers yellow; the connective with a dorsal-basal blunt tooth; thecae 6.0-6.5 mm long, opening by a upright to ventrally inclined pore. Ovary 3-locular, 1/2 inferior, the superior portion terete, the apex truncate; style glabrous, 12-14 mm long; stigma truncate. Fruits globose, with the calyx persistent and slightly reflexed, 8.0-11.0 mm long, black, sparsely glandular setose. The seeds not evident through the pericarp, truncate-obovate, 0.7-1.3 mm long, without capitate trichomes in the raphal area, without sculpturing, anticlinal walls straight, periclinal walls flat, boundaries between periclinal walls flat. Chromosome number n= unknown.

Taxonomy and Systematics: Tococa obovata is closely related to T. liesneri and T. oligantha, but it can be distinguished from both species by its large petals. Additionally, T. obovata can be distinguished from T. oligantha by the outer calyx which is reduced in the latter and developed in the former. Tococa obovata has 5-nervate leaves while T. liesneri has 3-nervate leaves. The two subspecies of T. obovata only differ in the shape and surface of their leaves but are identical in all other aspects. Some of the specimen duplicates for T. obovata subsp. neblinensis show leaves without domatia, but with foveolate leaves. Given that it is not possible to determine from these specimens whether they all belonged to the same individual or not, it is impossible to say if the presence of domatia is polymorphic in the population, or if it is merely that smaller individuals or branches closer to the ground lack domatia (as in T. rotundifolia). The domatia present in T. obovata are extremely reduced compared to those of the remaining species of Tococa, however detailed examination of some of them has revealed the presence of ants.

Key to infraspecific species:

1: Leaf surface flat.......... T. obovata subsp. obovata

2: Leaf surface foveolate.......... T. obovata subsp. neblinensis