Tococa pachystachya Wurdack

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Tococa pachystachya Wurdack

  • Primary Citation

    Mem. New York Bot. Gard. 10(4): 43, fig. 33 C-G. 1961

  • Type Specimens

    Specimen 1: Holotype -- B. Maguire 37368

  • 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: Cerro La Neblina, 1600 m, 24 JAN 1954, Maguire, Wurdack & Bunting 37368 (holotype NY; isotypes F, K, US, VEN).

    Description: Shrub, to 0.5-3.0 m tall. Stems densely glandular setose, the trichomes 2.5-3.5 mm long, persistent, the nodes glabrous. Petioles (0.5-) 1.0-2.5 cm long, glandular setose. Leaves anisophyllous, elliptic to ovate, the large leaves (7.5-) 10-21 (-26) x (3.5-) 6-9.5 (-12) cm, the short leaves 4-9 x 2-4.5 cm, apex shortly acuminate, base cordate, the sinus up to 6 mm long, adaxial surface adpressed-setose, abaxial surface glandular setose, the nerves densely setose or pilose, light green, with (2-)3 pairs of secondary veins, plinervate in the leaves with domatia, the first pair of secondary veins merging with the primary vein at the apex of the domatium, with 3 pairs of secondary veins, basally nervate in the leaves without domatia, membranaceous, ciliate-serrulate; domatia 1/2 to completely immersed in the leaf blade, narrowly ovoid, the apex truncate, 2.0-2.5 (-3.5) x 0.7-1.5 cm, strigose in the abaxial surface, the trichomes up to 3.5 mm long, their bases up to 1 mm wide, red or crimson. Inflorescence a terminal raceme, of 10-20 flowers, 6-15 (-22) cm long, the axis green, quadrangular, fleshy. Flowers sessile, subtended by persistent bracts, ovate, 2-3.5 x 1.5-1.8 mm; hypanthium globose, 3.0-3.2 mm long, glabrous; sepals broadly deltoid, connate 2/3 to 4/5 of the length, 1.0-1.8 mm long, calyx teeth broadly triangular, adnate to the sepals, terminated on one or two glandular setae up to 2.5 mm long; the ring inside the torus glabrous. Petals 5, oblong, 6.5-7.5 x 4.0-4.5 mm, base oblong to slightly attenuate, truncate, smooth, glabrous, orange to brown. Stamens all of the same size, the filaments 4 mm long, glabrous; anthers yellow; the connective without a dorsal-basal blunt tooth; thecae incurved, 3.5-4.0 mm long, opening by a ventrally inclined pore. Ovary 4 locular, 2/3 inferior, the superior portion sulcate, the apex broadly conical, truncate; style glabrous, 6.0-7.5 mm long; stigma funneliform to capitate, papillose. Fruits globose, 4-6 mm long, purple, glabrous. The seeds not evident through the pericarp, triangular, 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.

    Habitat and Distribution: Endemic to Cerro La Neblina and Cerro Aracamuni in S Venezuela and N Brazil. Growing in cloud forests, tepui scrub and ravines from 750 to 2100 m.

    Taxonomy and Systematics: Tococa pachystachya is easily distinguished from all other species of Tococa by its quadrangular racemose inflorescences, orange to brownish petals and the pubescence of the domatia. The morphological cladistic analysis shows it to be nested within the Tococa sensu stricto clade, in spite of the morphology of the anthers being fairly different from other species. However seed and calyx morphology resembles that of other species of Tococa sensu stricto. Wurdack has annotated one specimen from Neblina (M. Nee 30648) as T. pachystachya var. glabrata, but this specimen corresponds with little doubt to T. erythrophylla. Even though T. pachystachya has a very restricted distribution, it is locally abundant.

  • Floras and Monographs

    Tococa pachystachya Wurdack: [Article] Michelangeli, Fabián A. 2005. (Melastomataceae). Fl. Neotrop. Monogr. 98: 1-114.

    Tococa pachystachya Wurdack: [Article] Maguire, Bassett & Wurdack, John J. 1961. The botany of the Guayana Highland--part IV (2). Mem. New York Bot. Gard. 10: 1-87.