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| Miconia rheophytica Posada‒Herrera & Almeda
in Posada-Herrera & Almeda, 2018
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Abstract
Miconia rheophytica is described, illustrated, and compared with presumed relatives in the Octopleura clade. It is distinguished by its narrowly elliptic to ovate-lanceolate leaf blades with entire to subentire margins that have evenly spaced spreading smooth eglandular trichomes 0.8−1.4 mm long, an indumentum of dendritic trichomes with short axes and terete radiating arms on distal internodes, adaxial petiole surfaces, and primary and secondary veins on abaxial leaf surfaces, unribbed hypanthia that are constricted and tapered distally below the torus and covered with a mixture of basally roughened trichomes and dendritic trichomes with short axes, anthers with two ± truncate apical pores, eglandular anther appendages, 3-locular ovary, and berries that are bright blue at maturity. It is known only from flash-flooded riverbanks in three river canyons in the Magdalena Medio region of Antioquia, Colombia. A conservation assessment of “Endangered” is recommended for this species based on IUCN Red List Categories and Criteria.
Keywords: Andes, rheophyte, endangered species, neotropics, Octopleura clade, Eudicots
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| Figure 1. A. Habit. B. Cauline node and internode enlargement. C. Leaf apex, showing evenly spaced smooth marginal trichomes. D. Dendritic trichome with terete radiating arms. E. Simple axillary dichasium. F. Flower at anthesis (profile view). G. Elongated trichome with roughened base. H. Petal, showing reflexed posture. I. Stamen (profile view). J. Seeds, dorsal view (lower) and profile view (upper). All drawn from the holotype. |
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| Figure 2. Images of Miconia rheophytica. A. Habit with immature and mature berries. B. Flower and immature berries. C. Flower (at anthesis) and flower bud. D. Berry at maturity. Image credits: A, C, Rodrigo Bernal; B, D, Saúl E. Hoyos-Gómez. |
Miconia rheophytica Posada‒Herrera & Almeda, sp. nov.
Type:— COLOMBIA. Antioquia: Municipio de San Luis, río Samaná Norte, 2 km abajo del puente de la carretera Medellín‒Bogotá. ..., 430 m, 18 diciembre 2016 (fl, fr), S. E. Hoyos-Gómez 3105 (holotype: HUA!). Figs. 1, 2.
Diagnosis: Unusual and unique among species of the Octopleura clade in being rheophytic and in having a combination of narrowly elliptic to ovate-lanceolate leaf blades with entire to subentire margins that have evenly spaced spreading smooth eglandular trichomes 0.8−1.4 mm long, unribbed hypanthia covered with a mixture of basally roughened trichomes and dendritic trichomes with short axes, anthers with two ± truncate apical pores, eglandular anther appendages, 3-locular ovary, and berries that are bright blue at maturity.
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Distribution and habitat:— Miconia rheophytica appears to be largely restricted to the Magdalena Medio region of Colombia where it is known only from the Department of Antioquia (Fig. 3). It grows along rocky banks of Río Nechí, and in the Río Samaná Norte and Río Claro river canyons in the municipalities of Anorí and San Luis at elevations of 110−600 m.
Etymology:— The specific epithet is derived from the word rheophyte, a plant that grows along margins of fast moving river currents with frequent flooding. This is an environment that is particularly harsh for many organisms.
Juan Mauricio Posada-Herrera and Frank Almeda. 2018. Miconia rheophytica (Melastomataceae: Miconieae), A New and Endangered Species from the Magdalena Medio region of Colombia. Phytotaxa. 371(1); 55–61. DOI: 10.11646/phytotaxa.371.1.7
