Microlicia caatingae J. Coelho & R. Romero, 2018

Jesus, Jôane Coelho De, Romero, Rosana & Roque, Nádia, 2018, Two new species of Microlicia (Melastomataceae) from the Septentrional Espinhaço, Bahia, Brazil, Phytotaxa 343 (3), pp. 240-248 : 241-244

Microlicia caatingae J. Coelho & R. Romero , sp. nov.

Type:— BRAZIL. Bahia: Licínio de Almeida , Garimpo das Ametistas, rocky caatinga, 823 m alt., 14º31’44,1”S, 42º32’41”W, 23 March 2017, fl. fr., Coelho, Stadnik, Silva & Tuler 165 (holotype: ALCB!; isotypes: CEPEC!, HUEFS!, HUFU!, NY!, RB!, UPCB!). ( Figures 1–2 ) .

Diagnosis:— The new species resembles Microlicia confertiflora and M. cordata but differs by the branches with dense indumentum, petiole 0.5–1 mm long, leaf blade commonly with revolute margins, hypanthium 10-costate and abaxial surface of the sepals with long-stalked golden gland-tipped trichomes.

Erect shrub, ca. 1.5 m tall. Young branches quadrangular covered with spherical, golden glands and with sparse setose trichomes, older branches becoming terete, nodes frequently with setose trichomes 0.8 ‒ 1.5 mm long, glabrous and leafless with age, leaf scars conspicuous, internodes 1.5 ‒ 5 mm long. Leaves decussate, horizontal, not imbricate, discolorous, abaxial surface light green, apex and margin reddish in young leaves, frequently becoming reddish on the whole extension of the adaxial face of the older leaves (in fresh material); petiole 0.5–1 mm long, compressed; leaf blade ovate, of different sizes along the branches, 2.5–7.1 × 1.5–4.3 mm, apex obtuse, sometimes mucronate in young leaves, base rounded, margin entire, flat to revolute, both surfaces covered with impressed, spherical, golden glands, large leaves (1-) 3 nerved, small leaves with only one central vein evident. Floral bud with rose to magenta petals and lilac margins. Flowers solitary, lateral or terminal, 5-merous, zygomorphic; pedicel short, ca. 0.5 mm long, covered with spherical, golden glands, occasionally with setose trichomes at the base; hypanthium green becoming vinaceous at maturity (in fresh material) to brownish (in dried material), terete, 3.3–4.6 × 2.5–3.4 mm, 10-costate, covered with spherical, golden glands; sepals green-vinaceous, triangular, ca. 1.3 × 1.3 mm, apex acute with a glandular trichome, ca. 0.9 mm long, glands deciduous, abaxial surface with spherical, golden glands and long-stalked, golden gland-tipped trichomes 0.7–1 mm long, adaxial surface glabrous; petals lilac, oblong to obovate, 8.8–10.2 × ca. 5.5 mm, apex asymmetrical, retuse, acute to round, base attenuate, margin entire, glabrous; stamens 10, dimorphic, antesepalous 5, filaments lilac, 3.5–4 mm long, pedoconnective lilac, 5–5.5 mm long, ventral appendage light beige, rounded, ca. 1 mm long, anthers magenta, oblong, ca. 3 mm long (including rostrum), polysporangiate, rostrum white, ca. 1 mm long, antepetalous 5, filaments lilac, ca. 4–4.5 mm long, pedoconnective white becoming yellow, 1.5–2 mm long, not appendaged, anthers yellow, oblong, ca. 2 mm long (including rostrum), rostrum beige, ca. 0.5 mm long; ovary pyriform, 1.8 ‒ 2.5 × 1 ‒ 1.2 mm, superior, 3-locular, glabrous, style lilac, 7–8 mm long, curved at the apex, stigma magenta, punctiform. Capsule vinaceous, becoming brown in the mature fruits, ovoid, 3.3 ‒ 4.5 × 2.5 ‒ 3.3 mm, dehiscing into 3 valves from the apex, hypanthium recovering the capsule and gradually peeling off until fully exposing the fruit; seed oblong, slightly curved, 0.4–0.7 mm long, testa foveolate.

Additional specimens examined:— BRAZIL, BAHIA, Licínio de Almeida, Serra Geral, Arredores do Brejinho das Ametistas, 900–1000 m, 14°15’59” S, 42°31’28” W, 12 March 1994, fl. fr., N. Roque et al. CFCR 14974 (CAS, MO, P, US) ; Garimpo das Ametistas, 839 m, 14°31’44” S, 42°32’44” W, 14 July 2011, fl. fr., N. Roque et al. 3132 (ALCB, HUEFS) ; Riacho Fundo, 849 m, 14°35’13” S, 42°32’24” W, 10 October 2012, fl. fr., N. Roque et al. 3474 (ALCB, HUEFS) ; Garimpo das Ametistas, 28 May 2014, fl. fr., J. Coelho et al. 36 (ALCB, NY, RB) ; Riacho Fundo , 6 August 2014, fl. fr., N. Roque 4406 (ALCB, HUEFS), Garimpo das Ametistas, 14 May 2015, fl. fr., J. Coelho et al. 72 (ALCB, HUFU, UPCB) ; idem, 1 May 2016, fl. fr., J. Coelho et al. 125 (ALCB, HUEFS, RB) .

Distribution, habitat and conservation status:— Microlicia caatingae has been recorded so far only in the Serra Geral, Licínio de Almeida municipality, in Bahia state, Brazil ( Figure 3 ). The specimens were found only in rocky caatinga vegetation, on sandy soil and between 826 and 870 m of elevation. Recent floristic study in the area has described rocky caatinga (caatinga rupestre) as a phytophysiognomy with xeromorphic aspects and predominance of herbs and shrubs (rarely trees) up to 3 m tall among rocky outcrops, on shallow soils and elevations varying from 750 to 1000 m ( Campos et al. 2016). Microlicia caatingae occurs in area with anthropogenic degradation by both the extraction of amethyst (“Garimpo das Ametistas”) and by the suppression of vegetation following the expansion of wind farms (“Riacho Fundo”). Based on georeferenced data from cited collections, the area of occupancy was calculated using GeoCAT ( Bachman et al. 2011). Due to the restricted extent of occurrence and area of occupancy (AOO= 12 km 2), M. caatingae should be considered CR B1ab (iii) + 2ab (iii) according to IUCN categories and criteria (2001, 2014), with special attention to a critically endangered category (CR).

Etymology:— The specific epithet refers to the restricted occurrence of the new species to the Brazilian vegetation known as caatinga, in the Septentrional Espinhaço, in Minas Gerais and Bahia states.

Discussion:— The presence of dense indumentum between the leaves, petiole 0.5–1 mm long, leaf blade commonly with revolute margins, hypanthium 10-costate and abaxial surface of the sepals with long-stalked golden gland-tipped trichomes, distinguish Microlicia caatingae from other species of the genus. However, some flowers in the collection N. Roque et al. CFCR 14974 lack the long-stalked trichomes on the abaxial surface of the sepals. Microlicia caatingae resembles Microlicia confertiflora Naudin (1845: 176) which also occurs in Minas Gerais and Bahia states ( Romero & Woodgyer 2017), by having leaves with different sizes along the branches, ovate leaf blade, obtuse apex, covered with spherical, golden glands and dimorphic and bicolor stamens. However, M. confertiflora differs by its sessile leaves, smooth hypanthium and sepals covered only with spherical golden glands. Microlicia caatingae also shows a reddish color at the apex and margin of the young leaves, occasionally becoming completely reddish in the older leaves. This coloring is commonly maintained in dry material and was not observed in M. confertiflora . Microlicia caatingae also resembles Microlicia cordata Sprengel (1820: 301) Chamisso (1834: 390) by having ovate leaf blade with different sizes along the branches. However, M. cordata has hirsute indumentum in the branches and flowers with a long pedicel (1–3 mm long) ( Bacci et al. 2016).

The formula for M. caatingae in the multi-access key to the species of Microlicia in Bahia ( Woodgyer 2005) is BDHLOQUVae.

Figures

FIGURE 1. A–J: Microlicia caatingae. A. Flowering branch. B. Floral bud showing hypanthium and sepals. C. Leaf (abaxial surface). D. Mucronate apex in young leaf. E. Flower. F. Petal. G.Antesepalous stamen. H.Antepetalous stamen. I. Gynoecium. J. Fruit. (drawn from J. Coelho 125).

FIGURE2. A–E: Microlicia caatingae. A. Shrub habit. B. Floral buds and leaf arrangement. C. Flower. D. Floral buds in three stages of development. E. Fruit. (Photographs: J. Coelho).

FIGURE 3. Map of the municipality of Licínio de Almeida, Espinhaço Range, and pictures taken from rocky caatinga and rocky field (Photographs: L. Campos).