Tococa macrosperma Mart.
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Authority
Michelangeli, Fabián A. 2005.
(Melastomataceae). Fl. Neotrop. Monogr. 98: 1-114. (Published by NYBG Press) -
Family
Melastomataceae
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Scientific Name
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Type
Type. Brazil. Amazonas: Martius s.n. (holotype, G).
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Synonyms
Myrmidone macrosperma (Mart.) Meisn., Myrmidone lanceolata Cogn., Hormocalyx hirsutus Gleason
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Description
Species Description - Shrub, to 0.5-2.0(-3.0) m tall; stems with a mix of glandular and nonglandular setae, the trichomes 2.0-3.0 mm long, occasionally barbed, persistent, the nodes glabrous, occasionally developing adventitious roots near the base of the stem. Leaves anisophyllous, the larger ones elliptic to oblong, 8-22(-29) X 4-13 cm, the smaller ones oblong to lanceolate, 2-6 XI-3 cm, apex shortly acuminate, base cordate, adaxial surface adpressed-setose, abaxial surface sparsely adpressed-setose, the primary and secondary veins densely glandular- and nonglandular-setose, light green, shortly 5(-7)-plinervate, membranaceous, ciliate-serrulate; petioles 0.3-1.5(-3.5) cm long, with a mix of glandular setae and occasional barbed trichomes; domatia present in the larger leaves, rarely in the smaller leaves, ½ to completely immersed in the leaf blade, scrotiform, 1.0-2.5(-3.5) X 0.8-2.2(-3.0) cm, with trichomes up to 12 mm long. Flowers solitary or in dichasia, initially terminal, but quickly becoming axillary by overgrowth of the lateral meristem, often subtended by 2 small leaves (up to 3 cm long). Flowers on pedicels 1.0-2.0 mm long, not flared at the apex; bracts absent; hypanthium broadly conical, but quickly becoming globose, 3.5-4.5 mm long, glandular-setose, occasionally the trichomes densely barbed; outer calyx teeth connate, forming a skirt around the hypanthium, 2.0-2.5 mm long, terminated in 1 or more glandular setae, up to 4 mm long, inner calyx teeth completely connate or nearly so, 2.0-3.0 mm long, glandular-pubescent; the ring inside the torus glabrous; petals 6, oblong to ovate, 11-22(-25) X 4.5-7.0 mm, base oblong to slightly attenuate, apex emarginate, occasionally with caducous sessile glands in the margins near the base, rarely with 1 or more short glandular setae at the apex, the surface smooth, bright pink to dark red on the abaxial surface, becoming white after anthesis, white on the adaxial surface; stamens all the same size; filaments 5.0-8.0 mm long, glabrous; anthers yellow; the connective with or without a dorsal-basal blunt tooth; thecae 3.0-4.0 mm long, opening by a ventrally inclined pore; ovary 3-locular, 2/3 inferior, the superior portion conical, without a ring around the style, the apex with a corona of glandular setae; style glabrous, 8-11 mm long; stigma capitate, 1.5-2.0 mm wide. Fruits globose, 4.5-8.0 mm long, black, glandular-setose; seeds not evident through the pericarp, ovate, 1.2-2.8 mm long, without capitate trichomes in the raphal area, without sculpturing, anticlinal walls straight, periclinal walls flat, boundaries between periclinal walls raised.
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Discussion
Tococa macrosperma was originally described by Martius (1832) in the genus Tococa but on the next page of the same publication segregated into its own genus, on the basis of its unique calyx and large seeds. Several researchers have agreed that Myrmidone is closely related to Tococa and even that it is solely a segregate (see discussion on the phylogenetic relationships in this monograph). Wurdack (personal communication) kept Myrmidone as a separate genus not only on the basis of the calyx and seeds, but also due to the lack of the dorsal tooth in the anther connective. However, during the course of this study, it became evident that T. macrosperma is polymorphic for this character, so it should not be used as a diagnostic character to separate the two genera. Additionally, the morphological cladistic analysis presented here shows that T. macrosperma is nested within Tococa sensu stricto. The description of Hormocalyx hirsutus notes that the ovary is 2-locular, but all the specimens examined during this study had 3-locular ovaries.
The differences between Myrmidone lanceolata and T. macrosperma involve characters that are highly variable across populations, and do not support the recognition of separate taxa. Tococa macrosperma is closely related to T. rotundifolia with which it shares extreme anisophylly and domatia immersed in the leaf blade. Additionally, these two species have pseudoaxillary inflorescences with one or two flowers and bright red petals. Tococa macrosperma can be distinguished by the larger leaves and the connate outer calyx teeth that form a skirt around the hypanthium. Tococa macrosperma is often confused with various species of the genus Maieta Aublet. Even though these two taxa are superficially similar, they can be easily distinguished by the floral characters given above. Additionally, the anthers of Maieta are incurved with the thecae extending basally beyond the point of attachment with the connective. Vegetatively, they can be distinguished by the leaf base and the shape of the domatia: in T. macrosperma, the leaves are cordate and the domatia are scrotiform, whereas in Maieta, the leaves are attenuate at the base and the domatia are narrowly elliptic to fusiform and completely immersed in the leaf blade. Tococa macrosperma is usually found in the understories of forests and is usually associated with timid ants of the genera Crematogaster and Pheidole. Plants found above the 700 m often do not have ants inhabiting the domatia (Michelangeli, 2000b). The leaves of T. macrosperma are used by Baré Amerindians in southern Venezuela to prepare a tea that is given to their pregnant women if a girl is desired. -
Distribution
S Colombia and Venezuela, NE Peru, and N Brazil, in the understories of tierra firme forests, occasionally in the savanna-forest ecotone, from 50-1100 m.
Vaupés Colombia South America| Amazonas Venezuela South America| Bolívar Venezuela South America| Guyana South America| Amazonas Brazil South America| Mato Grosso Brazil South America| Pará Brazil South America| Rondônia Brazil South America|