Miconia astrocalyx Meirelles & R.Goldenb., 2016

Meirelles, Julia, Lima, Duane Fernandes & Goldenberg, Renato, 2016, Miconia astrocalyx (Melastomataceae, Miconieae): a new species from Brazilian Cerrado, Phytotaxa 257 (2), pp. 187-192 : 188-191

Miconia astrocalyx Meirelles & R.Goldenb. , sp. nov.

Distinguished among the species in Miconia sect. Miconia subsect. Seriatiflorae by the following set of features: branches and abaxial leaf surface with stellate yellowish indumentum (versus arachnoid whitish indumentum in M. fallax , M. stenostachya , M. ferruginata and M. weddellii ); large calyx lobes persistent in fruit (versus caducuous in M. ferruginata and M. herpetica ); petal margins with glandular-stipitate trichomes (versus glabrous in M. ferruginata and M. herpetica ); connective appendages ventrally slightly bilobed, with a very small dorsal inconspicuous tooth (versus skirt-like in M. ferruginata , M. herpetica , and M. weddellii ).

Type:— BRAZIL. Bahia: Rio de Contas, Estrada para Marcolino Moura após km 2, 21 February 2014 (fr), J. Meirelles & D. F. Lima 905 (holotype: UPCB!; isotypes: INPA!, K!, MBM!, MG!, NY!, HUEFS!, CEPEC!, RB!, US!). Figures 1–3 .

Trees or shrubs up to 3 m high; young branches, petioles, abaxial surface of the leaves, thyrses, outer surface of the hypanthium and outer surface of the calyx lobes densely covered with yellowish, sessile, stellate trichomes. Young branches flattened, canaliculate, without interpetiolar line. Leaves opposite and with the same size, strongly discolorous; petioles 0.8–1.6 cm; blades 7.5–10 × 3.5–5 cm, oblong, base cordate, attenuate to acuminate, margin slightly crenulate, coriaceous, longitudinal nerves 3, with an additional marginal pair; basal, main and secondary nerves strongly prominent on the abaxial surface, slightly sulcate on the adaxial; adaxial surface of young leaves sparsely to moderately covered by caducous stellate thichomes 0,3 diam. Inflorescence a thyrse 4.5–10 × 3–4.5 cm, terminal, the branches bifid and secund, each one with 3 to 7 flowers; bracts and bracteoles 1–3 mm long, lanceolate, persistent. Flowers 5-merous. Hypanthium 1–1.5 mm long, campanulate, inner surface with sparse glandular trichomes, otherwise glabrous. Calyx persistent, reddish and deflexed in fruit, inner surface glabrous but the basal line of the calyx lobes densely covered with unbranched, canescent trichomes; tube 0.4 mm long, lobes 1.8–2 mm long, triangular, teeth up to 0.2 mm long. Petals 3.5–4 × 3–3.3 mm, white, elliptic to shortly obovate, apex rounded, margins ciliate, with glandular-stipitate trichomes. Stamens yellow, dimorphic; filament 2.3–2.6 mm long (larger stamens) or 1.7–2 mm long (smaller stamens), glabrous; connective not prolonged below the thecae, ventrally slightly bilobed and with a very small dorsal inconspicuous tooth; anthers 3.1–3.5 mm long (larger stamens) or 2.8–3 mm long (smaller stamens), yellow, oblong, with a single, small, terminal pore, ca. 0.2 mm in diameter. Ovary 1.6 mm long, half fused to the hypanthium, 3-locular, apex with sparse glandular-stipitate trichomes, style 3.5–4 mm long, punctiform, with scattered glandular-stipitate trichomes on the basal half. Fruits baccate, 4.2–4.6 mm diam., purple; seeds ca. 1.6 mm long, pyramidal, testa smooth, cells with anticlinal walls undulate.

Distribution and ecology: — Miconia astrocalyx occurs in Rio de Contas, southwestern portion of Chapada Diamantina (state of Bahia), Posse (Goiás) and Serra das Confusões (Piauí), Brazil. The species has been collected in Cerrado and Caatinga, on white sandy or rocky soils, between 1000–1175 m elev.

Phenology:— Miconia astrocalyx was collected with buds and flowers from March to October, and with fruits from November to February.

Conservation Status: —Despite occurring inside a protected area (“Parque Nacional da Serra das Confusões”), this new species can be considered as endangered (EN) following the criteria B1bi ( IUCN 2014), due to its extension of occurrence (EOO) <5.000 km 2 and the continuous decline of the vegetation type where it occurs, the Cerrado.

Etymology: —The epithet refers to the star-shaped, 5-merous calyx lobes with acute apices and deflexed in fruit.

Comments: —This new species belongs to Miconia sect. Miconia subsect. Seriatiflorae , a group known by the inflorescences with flowers arranged in scorpioid (“secund”) branches (Cogniaux 1886–1888, 1891). It is related to the widespread M. fallax De Candolle (1828: 181) and M. stenostachya De Candolle (1828:181) , sharing with them the petals with glandular-stipitate margins and the anthers with connective appendages slightly ventrally bilobed. The distinctive characters between them ( Table 1) are the indumentum of the branches and abaxial surface of leaves (yellowish and stellate in M. astrocalyx vs. whitish and amorphous in the other two species), and the length of the calyx lobes (1.8–2 mm long in M. astrocalyx vs. 1.1–1.7 long in M. fallax and 0.8–0.9 long in M. stenostachya ). Additionally, the calyx lobes in M. astrocalyx are strongly deflexed in dried specimens.

Miconia astrocalyx is also similar to the poorly known M. weddellii Naudin (1850: 144) , from Cerrado vegetation. Both species have glandular-stipitate petal margins, stellate indumentum on branches and abaxial surface of leaves, and oblong leaves with rounded bases. However, M. weddellii has shorter and narrower inflorescences and leaves, and antesepalous stamens with skirt-like connective appendages plus a dorsal round projection (vs. slightly ventrally bilobed in M. astrocalyx ).

Miconia herpetica De Candolle (1828:181) is another poorly collected species from the same taxonomic group, and also occurring in Cerrado vegetation in Bahia and Minas Gerais. It shares with M. astrocalyx the yellowish stellate indumentum and oblong leaves, but differs by the petals with glabrous margins (vs. glandular-stipitate in M. astrocalyx ), stamens with skirt-like connective appendages (vs. slightly ventrally bilobed in M. astrocalyx ) and caducous calyx (vs. persistent in M. astrocalyx ).

Miconia astrocalyx also resembles a remarkable species from Cerrado that has inflorescences with scorpioid branches, M. ferruginata De Candolle (1828: 181) . Both species share the discolorous oblong leaves with stellate trichomes on the abaxial leaf surface. Nevertheless, M. ferruginata has longer and wider leaves, petals with glabrous margins (vs. glandular-stipitate in M. astrocalyx ), and caducous calyx (vs. persistent in M. astrocalyx ).

Paratypes: — BRAZIL. Bahia: Água Quente , Pico das Almas, 42º00’ W, 13º31’ S, 17 December 1988 (fr.), Harley et al. 27590 (K!). Barreiras, Estrada para Acaba a Vida, 45º36’W, 12º02’S, 24 March 1984, Moreira & Almeida 06 ( MG!). Rio de Contas , 6 km north of Rio de Contas on Road to Abaira, 41º47’ W, 13º33’ S, 16 January 1974 (fr.), Harley et al. 15112 (K!, RB!) ; 16 January 1974 (fr.), Harley et al. 15120 (K!); 5 km E. of Rio de Contas on the Marcolino Moura road, 41º48’ W, 13º55’ S, 27 March 1977 (fl.), Harley et al. 20052 (K!, NY!) ; Serra do Marcelino , 41º49’51” W, 13º 35’33” S, 2 February 1997 (fr.), Passos et al. 4848 ( HUEFS!) ; Estrada Rio de Contas para Marcolino Moura, km 1.5, 41º47’52” W, 13º36’16” S, 18 Nov 2000 (fr.), Baumgratz 719 ( RB!) ; 2.6 km da cidade em linha reta, na estrada para Arapiranga , 41º47’34” W, 13º34’13” S, 27 November 2004 (fr.), Harley & Giulietti 55238 ( UPCB!). Goiás: Posse, Arredores, 8 October 1976 (fl.), Hatschbach 39074 (MBM!, US!) . Piauí : Caracol , Parque Nacional da Serra das Confusões, 43º29’6” W, 9º13’17” S, 22 June 2007, Santos et al. 1440 ( HUEFS!) .

Figures

FIGURE 1. Miconia astrocalyx. A. Branch with fruits. B. External surface of the hypanthium and calyx. C. Detail of the calyx external teeth. D. Internal surface of hypanthium and calyx, in longitudinal section. E. Petal. F. Anthers with connectives and small bilobed appendages. G. Style.A: Harley 27590 (K). B–I: Hatschbach 39074 (US).

FIGURE 2. Miconia astrocalyx. A. Branch with fruits. B. Young leaf, adaxial surface. C. Yellowish indumentum on the branch and abaxial surface of the leaves. D. Inflorescence with mature fruits. E. Fruit with the reflexed calyx lobes. F. Cerrado vegetation, grasslands, and the mountains in Rio de Contas.A–E: Meirelles & Lima 905.

FIGURE 3. Miconia astrocalyx. A–B. Indumentum on the abaxial surface of the leaf. C. Seed. D. Seed surface.A–D: Hatschbach 39074 (US). Scale bars: A. 300 μm. B. 60 μm. C. 250 μm. D. 60 μm.