Microlicia nervosa R. Romero, 2013

Romero, Rosana, 2013, A new species of Microlicia (Melastomataceae) from the Espinhaço Range, Minas Gerais, Brazil, Phytotaxa 88 (1), pp. 1-5 : 1-5

Microlicia nervosa R. Romero , spec. nov. ( Figs. 1–2 )

Type:— BRAZIL. Minas Gerais: Estadual do Biribiri, Alto da Jacuba , 1382 m, 18°'32" S, 43°36'32" W, 14 March 2012, I. M . Araújo, D. Marques & I. M . Franco 252 (holotype HUFU!; isotypes BHCB!, DIAM!, K!, P!, RB!) .

Erect subshrub or shrub, 0.5–1.5 m tall, much branched. Young branches fastigiate, quadrangular, indumentum of young branches, adaxial and abaxial surface of the leaves, pedicel, hypanthium and calyx lobes with pale, glandular trichomes 0.1–0.3 mm long and sessile golden glands, older branches brown, furfuraceous, becoming slightly terete with age, without leaves at the base, nodes thickened. Leaves ascending, imbricate or not, coriaceous, discolorous, adaxial surface dark green, abaxial surface pale green (assessed when dry), petiole 1–2 × 0.8–1 mm, flattened, smooth, clearer, greenish-cream, sometimes tinged with pink; blade broadly elliptical to obovate, large leaves 8–11.5 × 4–8 mm, small leaves 4–8 × 2–4 mm, apex rounded to slightly acute, base attenuate, rarely rounded, margin entire, 3-nerved from the base, the nerves conspicuously visible on both surfaces, central nerve thickened and prominent on abaxial surface, ca. 0.5 mm wide at the middle of the lamina, adaxial surface with sparse indumentum. Flowers solitary, terminal or lateral, 5-merous, zygomorphic resulting from the position of the stamens and style; pedicel 1.3–2.3 mm long. Hypanthium terete, oblong, 4–4.5 × 2–2.5 mm, green or green and dark pink; calyx tube 0.5–0.8 mm long; calyx lobes linear, 3.5–5 × ca. 0.5 mm, distant 0.7–1.5 mm long from each other, apex acute, with a thickened tip, ca. 0.5 mm long, sometimes with a glandular trichome ca. 0.7 mm long. Petals 7.5–9.5 × 4–5.5 mm, oblong to obovate, pink to pink-magenta, glabrous, apex acute, often asymmetrically so. Stamens 10, dimorphic in size: large stamens 5, filaments 5–6 mm long, pink, anthers 3.5–4 mm long (including beak), oblong, tetrasporangiate, pink or red, beak 0.7–1 mm long, white or pale pink, connective prolonged 3.5–4 mm, pink, with ventral appendage 1.5–2 mm long, truncate, bicoloured with a part pink and the apex yellow; small stamens 5, filaments 4.5–5.5 mm long, pink, anthers 3–3.5 mm long (including the beak), yellow, oblong, tetrasporangiate, beak 0.7–9 mm long, yellow, connective 1.5–1.7 mm prolonged, ventral appendage 1.3–1.7 mm long, truncate, yellow. Ovary ca. 3 × 2 mm, superior, 3-locular, glabrous; style 9–10 mm long, pink, terete, slightly curved, glabrous; stigma punctiform. Capsule 3.5–5 × 2.5–4 mm, brown, subglobose, dehiscing into 3 valves from the apex, hypanthium covering the entire ovary and peeling off as the fruit matures. Seeds 0.6–0.7 × ca. 0.3 mm, pale brown, testa foveolate.

Distribution and habitat: — Microlicia nervosa is known only from two localities (around Diamantina and Serra do Cipó) in the Espinhaço mountain range, Minas Gerais state, Brazil, where it seems to be endemic. The populations are quite small and grow in campo rupestre on quartzite rock outcrops between 1172 m and 1350 m elevation.

Etymology:— The specific epithet refers to the characteristically prominent and thickened nerves, clearly visible on both surfaces of the leaves, but mainly on the abaxial surface.

Specimens Examined:— BRAZIL. Minas Gerais: Serra do Cipó, km 131, Palácio , 4 February 1938, M . Barreto 8948, ( BHCB, HUFU). Idem, km 131, 22 April 1950, A. P . Duarte 2610 ( NY, US). Ibidem , entre os km 130 e 131, 5 April 1951, G. A . Black & Magalhães 51-11888 ( BHCB). Ibidem, Fazenda Palácio , 14 February 1972, G . Hatschbach & A . Ahumada 31558 ( MBM, NY, US). 2 km beyond Chapéu de Sol , 30 Jan 1980, R. M . King & F . Almeda 8358 ( UB, US). Ibidem, Rodovia Belo Horizonte-Conceição do Mato Dentro, ca. 4 km após córrego Chapéu do Sol , 12 January 1996, V. C . Souza et al. 10192 ( ESA). 16 km SW of Diamantina, 1370 m , 19 January 1969, H. S . Irwin et al. 22239 ( NY, UB, US). Ca. 20 km SW of Diamantina, 1300 m , 21 January 1969, H. S . Irwin et al. 22406 ( NY, US). Ca. 8 km N of Gouveia on road to Diamantina, 1220 m , 4 February 1972, W. R . Anderson et al. 35355 ( HUFU, NY, UB, US). Diamantina, Parque Estadual do Biribiri, 1172 m, 18°12'69"S- 43°37'24"W, 21 September 2010, R . Romero et al. 8326 ( HUFU, SPF) .

Discussion: — Microlicia nervosa can be easily recognized by its leaves of different sizes along the branches, attenuate base, the thickened and prominent nerves visible on both surfaces and the presence of a flattened petiole. These features make this species very distinctive within the genus, making it difficult to know who its closest relatives are within species of Microlicia ( Table 1).

Among the species that occur in Minas Gerais state, M. nervosa resembles M. avicularis Mart. ex Naudin (1845: 176) , which occurs in Pico do Itabirito, Serra do Ouro Branco, Serra do Caraça, Serra do Cipó, Diamantina , and Serro. Both have discolorous leaves, with a short petiole, leaf blades attenuate at the base, petals pink to pink-magenta and dimorphic stamens with bicolorous anthers. Microlicia avicularis differs in having lanceolate to widely elliptic leaves with obtuse to slightly acute apex, crenulate margin for the upper half and less evident nerves.

Microlicia nervosa also has some similarity with M. tomentella Naudin (1845: 174) , which occurs sympatrically in Serra do Cipó and Diamantina , but also in Jaboticatubas, Curvelo, and São Gonçalo do Rio Preto. Both are subshrubs to shrubs 0.5–1.5 m tall, with a similar branching pattern, ascending leaves, of different sizes along the branches, petals pink to pink-magenta and dimorphic stamens with bicolorous anthers. However in M. tomentella , the leaves are sessile and like the branches, hypanthium and calyx lobes, are covered by a dense indumentum of long, pale glandular trichomes with 0.2–0.5 mm long and sessile glands.

Microlicia elegans Naudin (1845: 187) , which occurs in Ouro Preto, Serra do Cipó, and Diamantina , like M. nervosa , has leaves with an entire margin and a prominent and thickened central nerve. The pattern of nerves is however quite different since the lateral veins are inconspicuous and sometimes absent. The leaves also vary from elliptic to widely elliptic, oval or orbicular, and the apex is acute to cuspidate-acute, or shortapiculate, and cordate or rounded to attenuate at base. None of the species found in Bahia and Goiás have a similarity to the new species.

Figures

FIGURE 1. A–L Microlicia nervosa (I.M. Araújo et al. 252). A. Branch. B. Leaf adaxial surface, showing prominent nerves. C. Leaf abaxial surface, showing indumentum of glandular trichomes and sessile glands. D. Leaf adaxial surface, showing indumentum of sessile glands and glandular trichomes. E. Floral bud. F. Petal. G. Lateral view of large stamen. H. Lateral view of small stamen. I. Gynoecium. J. Detail of ventral appendage (large stamen). K. Detail of ventral appendage (small stamen). L. Capsule enclosed by the persistent hypanthium.

FIGURE 2. A–F. Microlicia nervosa (R. Romero et al. 8326). A. Branch with floral bud. B. Vegetative branch showing ascending leaves of different sizes. C. Flower. D. Two stages of immature fruit. E. Mature fruit. F. Habit (Photos: R. Romero).