Pleroma fontanae 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 : 242-245

2. Pleroma fontanae F.S.Mey., L.Kollmann & R.Goldenb. sp. nov. ( Figures 4–5 )

Diagnosis:— Pleroma fontanae differs from Tibouchina manicata by the older branches with conspicuous wings (3.1–5.8 mm high vs. inconspicuos wings, up to 0.8 mm high in T. manicata ), leaves sericeous on the adaxial surface (vs. strigose to setulose), shorter petioles (3.3–12.6 mm long vs. 30–40 mm long), flowers with shorter pedicels (1.8–2.5 mm long vs. 4–5.2 mm long), and wider velatidia (8.1–8.9 mm wide vs. 5–6.9 mm).

Type:— BRAZIL. Espírito Santo: São Roque do Canaã, Alto Misterioso , 13 November 2004 (fl.), A. P. Fontana, C. Esgario, R.C. de Brito, F. Fadini & L.N. Lima 1038 (holotype: UPCB!; Isotype: MBML!) .

Erect shrub 0.5–1.5 m tall. Younger branches quadrangular, angulose, older branches quadrangular, strongly winged, with wings 3.1–5.8 mm long, both moderately to densely setulose-villose, trichomes 0.3–1 mm long, usually eglandular, seldom glandular, curved, slightly enlarged at the base; nodes thickened. Leaves opposite; petioles 3.3–12.6 mm long; blades 3.4–9.2 × 2.3–6.5 cm, chartaceous, discolorous, ovate, base cordate, apex obtuse or cuspidate, 7–9 acrodromous nerves, the marginals confluent (meeting the secondaries at the leaf base before joing the midrib), if 9 the marginals tenuous, main nerves prominent, reticulation impressed on the adaxial surface, prominent on the abaxial surface, adaxial surface flat, soft, green or yellowish green, densely sericeous, trichomes 0.8–2 mm long, usually eglandular but seldom glandular, curved, slightly enlarged at the base, with branching near the base of the trichomes, abaxial surface flat, soft, yellow or white, densely villose on the surface and veins, trichomes 0.5–1.5 mm long, usually glandular but seldom eglandular, coiled, narrow at the base. Thyrsoids 9–19.5 × 4.5–7.5 cm, terminal, axis subterete, with the same indumentum as the branches, red; bracts late deciduous, leafy, petioles 0.8–4.5 mm long, blades 11.2–39.1 × 7.8–20.5 mm, elliptic, indumentum the same as on the leaves; bracteoles early deciduous, 5.8–13.8 × 2.9–4.6 mm, elliptic to lanceolate, apex acute, not covering the apex of the flower bud, margins entire, ciliate, adaxial surface glabrous, abaxial surface moderately setulose to setose, trichomes 0.2–1.2 mm long, eglandular, curved, slightly enlarged at the base. Flowers 5-merous, pedicels 1.8–2.5 mm long; hypanthium 5.2–5.8 × 3.4–4.4 mm, oblong, not costate, densely setulose, trichomes 0.6–1.6 mm long, glandular, curved, slightly enlarged at the base; sepals late deciduous, 5.2–7.1 × 2.3–3 mm, triangular, margins ciliolate, apex acute, adaxial surface glabrous, abaxial surface with the same trichomes as the hypanthium; petals dark purple with a white base, 22.4–26 × 23.2–26 mm, obovate, apex retuse to emarginate, forming an angle ≥ 90° in relation to the hypanthium (in living specimens); stamens 10, dimorphic, antesepalous with filaments white, 4.1–4.5 mm long, sparsely setulose on the lower half, trichomes 0.1–0.3 mm long, glandular, curved, narrow at the base, pedoconnective white, ca. 0.4 mm prolonged below the thecae, sparsely to moderately setulose, trichomes 0.1–0.4 mm long, glandular, erect, narrow at the base, ventral appendages bilobed, inconspicuous, ca. 0.2 mm long, sparsely to moderately setulose, trichomes 0.1–0.4 mm long, glandular, erect, narrow at the base, thecae 3.6–4 × 0.2–0.3 mm, filiform, very narrow, white, antepetalous stamens with filaments white, 3.9–4.2 mm long, sparsely to moderately setulose on the lower half, trichomes 0.2–0.4 mm long, glandular, curved, narrow at the base, pedoconnective white, 0.4–0.6 mm prolonged below the thecae, glabrous, ventral appendages bilobed, inconspicuous, ca. 0.1 mm long, glabrous, thecae 3.5–3.8 × 0.7–1 mm, widely and shortly falcate, thickened, white; ovary 4.4–5.2 × 2.5–2.8 mm, 5-locular, apex densely sericeous, trichomes 0.3–0.8 mm long, usually glandular but seldom eglandular, appressed, narrow at the base; style white, 4.6–5.5 mm long, apex curved, moderately to densely setulose on the lower half, trichomes 0.2–0.5 mm long, usually glandular but seldom eglandular, curved, slightly enlarged at the base, stigma orbicular. Velatidium 8.9–9.6.1 × 8.1–8.9 mm, costate, epicarp lacerated when mature.

Paratypes:— BRAZIL. Espírito Santo: Itaguaçu, Pedra do Caparaó, 10 April 2004 (fr.), A.P. Fontana et al. 856 (MBML!, UPCB!); ibidem, 17 June 2007 (fl.), L. Kollmann et al. 9950 (MBML!, UPCB!). São Roque do Canaã, Alto Misterioso, 19 March 2004 (fr.), C.N. Fraga et al. 1163 (RB!); ibidem, 13 November 2004 (fl.), A.P. Fontana et al. 1039 (MBML!, UPCB!); ibidem, 16 September 2005 (fl.), A.P. Fontana et al. 1718 [MBML 45330!, UPCB 82845!; not to be confused with the same collector and number, MBML 2340 and UPCB 60097, which are Behuria comosa Tavares et al. (2008: 158) ]; ibidem, 16 November 2006 (fl.), C. Esgario et al. 104 (MBML!, UPCB!); ibidem, 30 August 2007 (fl.), C. Esgario & A.P. Fontana 194 (MBML!, UPCB!).

Distribuition and habitat:— Pleroma fontanae is a rupicolous plant occuring on granitic and gneissic inselbergs at “Alto Misterioso” and “Pedra do Caparaó” (not “Serra do Caparaó”, in the border between Espírito Santo and Minas Gerais), between 1000–1300 m elevation, in areas with sparse vegetation, composed by shrubs and herbs.

Phenology:—Collected with flowers between June and November, and with fruits in March and April.

Conservation status:— Pleroma fontanae is restricted to only two severely fragmented localities; the AOO is 8 km 2, and the EOO is 5.550 km 2. The species does not occur inside any conservation unit, and the vegetation on the surroundings has been replaced with agriculture and reforestation. Therefore, following the criteria of the IUCN ( IUCN 2012), P. fontanae should be considered as Critically Endangered [CR: B1ab(i,ii,iii,iv,v)c(i,ii,iii,iv)+2ab(i,ii,iii,v)].

Etymology:—The epithet honors the botanist André Paviotti Fontana , the collector of the type and one of the most important plant collectors in Espírito Santo.

Affinities:— Pleroma fontanae is morphologically similar to T. manicata due to the thick nodes, ovate leaves with cordate base, inflorescences in apical thyrsoids with red axes, flowers with glandulose-setulose hypanthia, purple petals with a white base, antesepalous stamens with glandulose pedoconnective and appendages, and costate velatidia. It differs from T. manicata by the characters pointed in the diagnosis, and also by the antesepalous stamens with shorter thecae (3.6–4 mm long. vs. 5.3–6 mm long in T. manicata ).

Pleroma fontanae is also similar to P. heteromallum and its putative synonyms (see coments under P. cucullatum ) by the ovate leaves, flowers with purple petals with a white base, and the antesepalous stamens with glandular pedoconnectives and appendages. Pleroma fontanae differs from P. heteromallum and its putative synonyms by the strongly winged older branches, with wings 3.1–5.8 mm high (vs. inconspicuously winged, with wings 1.2–2.5 mm high in P. heteromallum and its putative synonyms) and wider, 8.1–8.9 mm wide velatidia (vs. narrow, 4.3–5.6 mm wide velatidia). Pleroma fontanae differs from P. multiflorum (one of the species synonymyzed under P. heteromallum ), by the older branches strongly winged, with wings 3.1–5.8 mm high (vs. wings 1–1.3 mm high in P. multiflorum ), shorter, 3.3–12.6 mm long petioles (vs. 10.2–19.1 mm long), and glandulose-setulose hypanthia (vs. eglandular and sericeous; Table 1).

Pleroma fontanae is also similar to Tibouchina clavata ( Persoon 1805: 476) Wurdack (1960: 233) , both with short petioles (3.3–12.6 mm long in P. fontanae and 1–2 mm long in T. clavata ), blades with a cordate base and sericeous on the adaxial surface. Pleroma fontanae differs from T. clavata by the glandulose-setulose hypanthia (vs. eglandular and sericeous in T. clavata ) and the antesepalous stamens with glandular trichomes on the pedoconnectives and appendages (both glabrous on T. clavata ).

Figures

FIGURE 4. Images of the holotype of Pleroma fontanae.A. Branch with inflorescence. B. Detail of the thickened node on the branches. C. Leaf (abaxial surface). D. Detail of the leaf indumentum (adaxial surface). E. Detail of the leaf indumentum (abaxial surface). F.Apex of the inflorescence. G. Bracteoles, variation in size (abaxial surface). H1. Antesepalous stamen. H2.Antepetalous stamen. I. Gynoecium. J. Velatidium (A–I: Fontana et al. 1038, J: Fontana et al. 856).

FIGURE 5. Photos of Pleroma fontanae. A. Natural habitat and habit. B. Leaves. C. Inflorescence. D. Flower. (Photos by L.J.C. Kollmann).