Taxon Details: Pleiochiton micranthum Cogn.
Taxon Profile:
 | The Plant List |
 | International Plant Name Index |
 | Tropicos |
 | Catalogue of Life |
 | Global Biodiversity Information Facility |
 | JSTOR Types |
| JSTOR |
 | BHL |
 | Encyclopedia of Life |
 | WikiSpecies |
 | Google Scholar |
 | PubMed |
 | Morphbank |
 | IUCN |
 | National Center for Biotechnology Information |
 | Barcode of Life |
Narratives:
Family:
Melastomataceae (Magnoliophyta)
Melastomataceae (Magnoliophyta)
Scientific Name:
Pleiochiton micranthum Cogn.
Pleiochiton micranthum Cogn.
Accepted Name:
This name is currently accepted.
This name is currently accepted.
Description:
Description Author and Date: Marcelo Reginato, José Fernando Andrade Baumgratz, and Renato Goldenberg, based on A Taxonomic revision of Pleiochiton (Melastomataceae, Miconieae). Reginato, M., Baumgratz, J.F.A., & Goldenberg, R. Brittonia, 65(1), 2013, pp. 16–41
Type: Brazil. Rio de Janeiro: “In Brasiliae prov. Rio de Janeiro, Alto Macahé”, 22 Dec 1887, A. Glaziou 16947a (holotype: BR, high resolution image in UPCB; isotype: P).
Description: Young branches, inflorescences and hypanthia sparsely covered by glandular trichomes, 1–1.5 mm long; petioles and abaxial leaf surface sparsely covered by eglandular trichomes on acrodromous nerves; older branches and adaxial leaf surface glabrous. Old branches 2.5–3 mm diam., nodes 5–7.5 mm diam. Leaves isophyllous; petioles 4–10 mm long; blade (5–)6.5–10.5 x (2–)3–5 cm, ovate or elliptic-lanceolate, chartaceous or coriaceous, apex acuminate, base cordate, margin slightly crenulate and revolute, sometimes flat, ciliate (trichomes 1.5–2 mm long); acrodromous nerves 5 or 5+2, basal or up to 3.5 mm suprabasal. Cymes 6.5–10 cm long, terminal or lateral, lax, 20-60-flowered, 3-4 pairs of paraclades plus an apical triad, anthopodia up to 10 mm long; bracts 1.2–2.5 mm long, oblong or ovate to lanceolate, ciliate, glabrous; bracteoles 0.8–2 mm long, not involucral. Flowers 5-merous, pedicels 0.2–0.5 mm long. Hypanthium 2–2.5 x 1.5–2.5 mm, campanulate, torus glabrous. Calyx tube 0.3–0.4 mm long, lobes 0.3–1 mm long, deltoid or slightly triangular; external teeth 1.2–2.2 mm long. Petals 2.7–4.4 x 1.7–2.6 mm, ovate or oblong, apex shortly acuminate. Stamens slightly unequal in size, the shorter filaments (2.5–)3.4–3.8 mm long, the longer ones 3.5–4.3 mm long; anthers yellow, dorsally arcuate, the shorter ones 2.1–3 mm long, the longer ones 3–4 mm long, pore dorsal; connective 0–0.35 mm prolonged below the thecae, unappendaged. Ovary 1/4–1/3 inferior, 1.8–2.3 x 1.1–1.7 mm, conical, apex glabrous; style 7–8.5 mm long. Berries 4–7 x 4–7 mm; seeds 1–1.1 x 0.7–0.8 mm, 50–85 per fruit.
Habitat and Distribution: This species is known only from “Macaé de Cima”, Nova Friburgo, Rio de Janeiro (Fig. 3D). Nevertheless, the species is common in the area and has been frequently collected in montane forest between 1000 and 1200 m above sea level, from 6 to 12 m high on the host.
Phenology: Pleiochiton micranthum was collected with flowers from June to November, and with fruits from March to May.
Taxonomy and Systematics: This species is recognized by the inflorescences 6.5–10 cm long, with more than three pairs of paraclades, each of which with more than 20 flowers, and by the short hypanthium (2–2.5 mm long). Besides, the flowers are pedicellate, the filaments are about twice as long as the hypanthium, and the ovary is conical. Among the species with coriaceous leaves and inflorescences with glandular trichomes, P. micranthum shares with P. setulosum the cordate leaf bases, pedicellate flowers and size of the calyx external teeth. Nonetheless, the sympatric P. setulosum has showy, cordiform bracts (vs. oblong to lanceolate), and the globose ovary (vs. conical). Pleiochiton roseum, which also has large leaves and inflorescences, differs from P. micranthum by congested triads and sessile flowers, and bracteoles covering the base of the hypanthium.
Description Author and Date: Marcelo Reginato, José Fernando Andrade Baumgratz, and Renato Goldenberg, based on A Taxonomic revision of Pleiochiton (Melastomataceae, Miconieae). Reginato, M., Baumgratz, J.F.A., & Goldenberg, R. Brittonia, 65(1), 2013, pp. 16–41
Type: Brazil. Rio de Janeiro: “In Brasiliae prov. Rio de Janeiro, Alto Macahé”, 22 Dec 1887, A. Glaziou 16947a (holotype: BR, high resolution image in UPCB; isotype: P).
Description: Young branches, inflorescences and hypanthia sparsely covered by glandular trichomes, 1–1.5 mm long; petioles and abaxial leaf surface sparsely covered by eglandular trichomes on acrodromous nerves; older branches and adaxial leaf surface glabrous. Old branches 2.5–3 mm diam., nodes 5–7.5 mm diam. Leaves isophyllous; petioles 4–10 mm long; blade (5–)6.5–10.5 x (2–)3–5 cm, ovate or elliptic-lanceolate, chartaceous or coriaceous, apex acuminate, base cordate, margin slightly crenulate and revolute, sometimes flat, ciliate (trichomes 1.5–2 mm long); acrodromous nerves 5 or 5+2, basal or up to 3.5 mm suprabasal. Cymes 6.5–10 cm long, terminal or lateral, lax, 20-60-flowered, 3-4 pairs of paraclades plus an apical triad, anthopodia up to 10 mm long; bracts 1.2–2.5 mm long, oblong or ovate to lanceolate, ciliate, glabrous; bracteoles 0.8–2 mm long, not involucral. Flowers 5-merous, pedicels 0.2–0.5 mm long. Hypanthium 2–2.5 x 1.5–2.5 mm, campanulate, torus glabrous. Calyx tube 0.3–0.4 mm long, lobes 0.3–1 mm long, deltoid or slightly triangular; external teeth 1.2–2.2 mm long. Petals 2.7–4.4 x 1.7–2.6 mm, ovate or oblong, apex shortly acuminate. Stamens slightly unequal in size, the shorter filaments (2.5–)3.4–3.8 mm long, the longer ones 3.5–4.3 mm long; anthers yellow, dorsally arcuate, the shorter ones 2.1–3 mm long, the longer ones 3–4 mm long, pore dorsal; connective 0–0.35 mm prolonged below the thecae, unappendaged. Ovary 1/4–1/3 inferior, 1.8–2.3 x 1.1–1.7 mm, conical, apex glabrous; style 7–8.5 mm long. Berries 4–7 x 4–7 mm; seeds 1–1.1 x 0.7–0.8 mm, 50–85 per fruit.
Habitat and Distribution: This species is known only from “Macaé de Cima”, Nova Friburgo, Rio de Janeiro (Fig. 3D). Nevertheless, the species is common in the area and has been frequently collected in montane forest between 1000 and 1200 m above sea level, from 6 to 12 m high on the host.
Phenology: Pleiochiton micranthum was collected with flowers from June to November, and with fruits from March to May.
Taxonomy and Systematics: This species is recognized by the inflorescences 6.5–10 cm long, with more than three pairs of paraclades, each of which with more than 20 flowers, and by the short hypanthium (2–2.5 mm long). Besides, the flowers are pedicellate, the filaments are about twice as long as the hypanthium, and the ovary is conical. Among the species with coriaceous leaves and inflorescences with glandular trichomes, P. micranthum shares with P. setulosum the cordate leaf bases, pedicellate flowers and size of the calyx external teeth. Nonetheless, the sympatric P. setulosum has showy, cordiform bracts (vs. oblong to lanceolate), and the globose ovary (vs. conical). Pleiochiton roseum, which also has large leaves and inflorescences, differs from P. micranthum by congested triads and sessile flowers, and bracteoles covering the base of the hypanthium.