Pleiochiton parasiticum (O.Berg ex Triana) Reginato, R.Goldenb. & Baumgratz

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Pleiochiton parasiticum (O.Berg ex Triana) Reginato, R.Goldenb. & Baumgratz

  • 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. Herb. Imp. Vind. 1169 (holotype: K; isotype: NY).

    Description: Young branches, leaves, inflorescences, and hypanthia moderately to densely covered by eglandular trichomes, 1–3 mm long, more densely so at petioles, acrodromous nerves on abaxial leaf surface and hypanthia; sometimes with mixed glandular trichomes at hypanthia; older branches glabrous. Old branches 1.4–3 mm diam., nodes 3–5.5 mm diam. Leaves anisophyllous in size in each pair (the bigger ca. 2–3 times longer than the smaller); petioles 5–20 mm long; blade 3–7.5 x 1–2.5 cm, ovate to elliptic-lanceolate, sometimes slightly obovate, membranaceous, the apex acute or shortly acuminate, the base obtuse or rounded, the margin slightly crenulate and flat, ciliate (trichomes 1.5–2.5 mm long); acrodromous nerves 5 or 3+2, up to 10 mm suprabasal, sometimes basal. Cymes (0.5–)1.5–6 cm long, terminal or lateral, lax, 1–7-flowered, with 1–2 pairs of paraclades plus an apical triad, rarely a solitary flower, anthopodia 4–12 mm long; bracts 2–6 mm long, lanceolate to oblong, rarely elliptic-lanceolate, ciliate, glabrous or sparsely covered by eglandular trichomes; bracteoles 2–6 mm long, not involucral or just partially. Flowers 5-merous, pedicels 0.4–1.2 mm long. Hypanthium 3.2–5 x 2.5–3 mm, tubular, torus with glandular trichomes (1 mm long). Calyx tube 0.5–1 mm, lobes totally adhered to the external teeth; external teeth (4.5–)6–7 mm long. Petals 4.5–6 x 2–3 mm, ovate or obovate, apex shortly acuminate. Stamens slightly unequal in size, the shorter filaments 3.5–6 mm long, the longer ones 4.5–7 mm long; anthers yellow, linear, the shorter ones 3.2–4 mm long, the longer ones 3.8–5 mm long, pore ventral; connective not prolonged below the thecae, unappendaged. Ovary 1/6–1/2 inferior, 2–3 x 2–2.5 mm, conical, apex with glandular trichomes (ca. 1.5 mm long); style 8.5–13 mm long. Berries 5.5–6 x 5–5.5 mm; seeds not seen.

    Habitat and Distribution: This species is also presents the distributional pattern Serra dos Órgãos/Serra da Bocaina, shared with P. roseum and P. crassifolium (Fig. 3D). It has been collected under shade and sometimes on rocks (rupicolous specimens), in forests from 900 to 1900 m above sea level.

    Phenology: Collected with flowers in March and April.

    Taxonomy and Systematics: This species is recognized by the membranaceous, anisophyllous leaves (the larger leaf from each pair about two or three times longer than the smaller), with a moderate to dense indumentum on both surfaces, the cymes with eglandular trichomes, bearing flowers in lax triads, the calyx inner lobes usually totally adhering the outer teeth (unilobed), and the gland ulose torus. The larger leaves are usually clearly suprabasal (lateral acrodromous nerves diverging up to 10 mm from the base), while the smaller leaves are slightly suprabasal (diverging up to 2 mm from the base). These clearly suprabasal leaves are not found elsewhere in the genus. Pleiochiton blepharodes seems to be the species that is morphologically closer to P. parasiticum (see comments under this species), with several specimens misidentified under P. parasiticum. Rizzini (1954) mentioned C. parasitica var. organensis Brade (nom. nud.), but this taxon was never published, and no specimens determined with this name have ever been found.

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