Pleroma venetiense F.S.Mey., L.Kollmann & R.Goldenb., 2018

Meyer, Fabrício Schmitz, Kollmann, Ludovic J. C., Fraga, Claudio Nicoletti De & Goldenberg, Renato, 2018, Four new rupicolous species of Pleroma (Melastomataceae) endemic to Espírito Santo, Brazil, Phytotaxa 348 (4), pp. 235-253 : 248-251

4. Pleroma venetiense F.S.Mey., L.Kollmann & R.Goldenb. sp. nov. ( Figures 8–9 )

Diagnosis:— Pleroma venetiense differs from Tibouchina radula by the leaves with shorter petioles (2.2–5.5 mm long vs. 10–20 mm long in T. radula ), ovate blade with cordate to slightly cordate bases (vs. elliptical to elliptical-lanceolate blade with acute to obtuse bases), and scabrous adaxial leaf surfaces (vs. strigose).

Type:— BRAZIL. Espírito Santo: Nova Venécia, Área de Proteção Ambiental – APA da Pedra do Elefante , 16 March 2016 (fl., fr.), L. O. Azevedo, L. F. A. Paula & R. C. Forzza 441 (holotype: UPCB!; Isotype: RB!) .

Erect shrub 0.3–1.2 m tall. Younger and older branches quadrangular, younger not winged, older angulose, with wings 0.6–1.1 mm long, both sparsely strigose, trichomes 0.2–0.6 mm long, eglandular, appressed, narrow at the base; nodes thickened. Leaves opposite; petioles 2.2–5.5 mm long; blades 4.4–7.1 × 2.4–4.5 cm, coriaceous, concolorous, ovate, base cordate to slightly cordate, apex acute to obtuse, 5–7 acrodromous nerves, basal, if 7 the marginals tenuous, main nerves prominent, reticulation impressed on the adaxial surface, prominent on the abaxial surface, adaxial surface flat, rough, dark green or brown, densely scabrous, trichomes 0.3–1.2 mm long, eglandular, appressed, immersed and with a many branched forked base, abaxial surface foveolate, soft, light brown to brown, densely hirsutulous on the surface and terciary veins, trichomes 0.1–0.3 mm long, eglandular, erect, narrow at the base, primary and secondary veins moderately to sparsely strigose, trichomes 0.3–0.9 mm long, eglandular, appressed, slightly enlarged at the base. Thyrsoid 28.5–31.5 × 4–7.5 cm, terminal, axis terete or subquadrangular, with the same indumentum as the branches, brown to greenish yellow; bracts late deciduous, leafy, petioles 2.2–3.4 mm long, blade 23.9–36.4 × 7–18.6 mm, ovate to lanceolate, indumentum the same as on the leaves; bracteoles early deciduous, 3.6–4.6 × 0.9–2.1 mm, ovate to lanceolate, apex acute to attenuate, not covering the apex of the flower bud, margins entire, ciliate, adaxial surface glabrous, abaxial surface densely strigose, trichomes 0.2–0.9 mm long, eglandular, appressed, slightly enlarged at the base. Flowers 5-merous, pedicels 1.2–1.5 mm long; hypanthium 4–4.6 × 2.7–3.1 mm, oblong, not costate, densely strigose, the trichomes 0.3–0.9 mm long, eglandular, appressed, with short lateral projections (dendritic), slightly enlarged at the base; sepals late deciduous, 4.8–5.5 × 1.8–2 mm, triangular, margins ciliolate, apex attenuate, adaxial surface glabrous, abaxial surface with the same trichomes as the hypanthium; petals purple with a white base, 22.1–23.2 × 20–21.2 mm, obovate, apex retuse to emarginated, forming an angle ≥ 90° in relation to the hypanthium (in living specimens); stamens 10, dimorphic, antesepalous with filaments white, 3.9–4.3 mm long, moderately setulose on the lower two-thirds, trichomes 0.1–0.3 mm long, glandular, curved, narrow at the base, pedoconnective white to light purple, 0.7–0.9 mm prolonged below the thecae, densely to moderately setulose, trichomes 0.2–0.4 mm long, glandular, erect, narrow at the base, ventral appendages bilobed, inconspicuous, ca. 0.2 mm long, densely to moderately setulose, trichomes 0.1–0.4 mm long, glandular, erect, narrow at the base, thecae 3.4–3.6 × 0.2–0.3 mm, filiform, narrow, white to light purple, antepetalous stamens with filaments white, 3.3–3.7 mm long, moderately setulose on the lower two-thirds, trichomes 0.1–0.4 mm long, glandular, curved, narrow at the base, pedoconnective white to light purple, ca. 0.4 mm prolonged below the thecae, glabrous or sparsely setulose, trichomes ca. 0.2 mm long, glandular, curved, narrow at the base, ventral appendages bilobed, inconspicuous, ca. 0.1 mm long, glabrous or sparsely setulose, trichomes ca. 0.2 mm long, glandular, curved, narrow at the base, thecae 3.2–3.4 × 0.5–0.6 mm, widely and shortly falcate, narrow, white to light purple; ovary ca. 3.1 × 2.4 mm, 5-locular, apex densely setulose, trichomes 0.2–0.6 mm long, usually glandular but seldom eglandular, erect, slightly enlarged at the base; style white, 2.7–3 mm long, apex curved, moderately setulose on the lower two-thirds, trichomes 0.2–0.4 mm, eglandular, curved, slightly enlarged at the base, stigma orbicular. Velatidium 6.8–7.8 × 5.2–6 mm, costate, epicarp undivided when mature.

Paratypes:— BRAZIL. Espírito Santo: Nova Venécia, Área de Proteção Ambiental – APA da Pedra do Elefante, 19 February 2008 (fl.), L. Kollmann et al. 10702 ( RB!, UPCB!) ; ibidem, 14 January 2009 (fl.), L. Kollmann et al. 11397 ( CEPEC!, MBML!, RB!) ; ibidem, 15 january 2009 (fl.), L. Kollmann et al. 11412 ( CEPEC!, MBML!, RB!) ; ibidem, 21 March 2016 (fl.), H. V. Pinto Junior 258 ( SAMES, UPCB!) ; Serra de Baixo, Pedra da Torre , 18 February 2008 (fr.), A. P. Fontana et al. 4845 ( MBM!, MBML!, RB!) .

Distribuition and habitat:— Pleroma venetiense is endemic to the “Área de Proteção Ambiental da Pedra do Elefante”, Espírito Santo, Brazil. It is a rupicolous plant, occuring in low, sparse vegetation on granitic and gneissic inselbergs between 400– 700 m.

Phenology:—Collected with flowers between January and March, and with fruits between January and March.

Conservation status:— Pleroma venetiense is represented by a few populations with scattered individuals; the AOO is 8 km 2 and the EOO is 1.008 km 2. These populations occur in the same areas as P. cucculatum , and are subject to the same conditions (see comments under this species). Therefore, following the criteria of the IUCN ( IUCN 2012), P. venetiense should be considered as Critically Endangered [CR: B1ab(i,ii,iii,v)+2ab(i,ii,iii)].

Etymology:—The epithet refers to the municipality of Nova Venécia, place of occurrence of the species. The municipality was founded mainly by Italian colonizers, and its name is a reference to the city of Venice, in Italy.

Affinities:— Pleroma venetiense is morphologically similar to T. radula and P. fornograndense due to the rough leaves on the adaxial surface, ovate to lanceolate bracteoles, strigose hypanthia, flowers with purple petals with a white base and antesepalous stamens with the pedoconnective covered with glandular trichomes. It differs from T. radula by the characters pointed in the diagnosis, and also by the coriaceous leaves (vs. chartaceous in T. radula ; Table 1). Pleroma venetiense differs from P. fornograndense by the smaller leaves (4.4–7.1 × 2.4–4.5 cm vs. 5.6–12 × 3–6.1 cm in P. fornograndense ), with trichomes with many-branched forked bases on the adaxial surface (vs. leaves with trichomes with non-forked bases on the adaxial surface). Pleroma venetiense is also similar to P. heteromallum and its putative synonyms (see comments under P. cucculatum ) due to the lanceolate bracteoles, flowers with purple petals with a white base and antesepalous stamens with the pedoconnective covered with glandular trichomes. Pleroma venetiense differs from P. heteromallum and its putative synonyms by the smaller leaves (4.4–7.1 × 2.4–4.5 cm vs. 12.5–21 × 8.5–15 cm in P. heteromallum and its putative synonyms) that are coriaceous (vs. chartaceous) and scabrous on the adaxial surface (vs. strigose). Pleroma venetiense differs from P. multiflorum (one of the species synonymyzed under P. heteromallum ) by the smaller leaves (4.4–7.1 × 2.4–4.5 cm vs. 6.8–11.2 × 4.2–6.2 cm in P. multiflorum ) that are coriaceous (vs. chartaceous), with a rough indumentum on the adaxial surface (vs. soft; Table 1).

Figures

FIGURE 8. Images of the holotype of Pleroma venetiense. A. Branch with inflorescence. B. Leaf (abaxial surface) C. Detail of the leaf indumentum (adaxial surface). D. Detail of the leaf indumentum (abaxial surface). E. Compound Cyme, apex of the inflorescence, with a mature velatidium on the central portion of the cyme. F. Bracteole (abaxial surface) G1. Antesepalous stamen. G2. Antepetalous stamen H. Gynoecium. I. Velatidium. (A–H: Azevedo et al. 441, I: Kollmann et al. 10702).

FIGURE 9. Photos of Pleroma venetiense. A. Natural habitat and habit. B. Leaf (abaxial surface). C.Apex of the inflorescence. D. Flower. (Photo A by L. Azevedo, B-D by L.J.C. Kollmann).