Myrcia trimera E.Lucas & Sobral, 2015

Sobral, Marcos, Faria Jr, Jair E. Q., Ibrahim, Marla U., Lucas, Eve J., Rigueira, Dary, Stadnik, Aline & Dcnat-Ufsj, Daniel Villaroel, 2015, Thirteen new Myrtaceae from Bahia, Brazil, Phytotaxa 224 (3), pp. 201-231 : 224-227

12. Myrcia trimera E.Lucas & Sobral , sp. nov. Type:— BRAZIL. Bahia: mun. Itacaré, Fazenda do Boa Paz, trilha do Boa Paz, 14°20’05”S, 39°01’94”W, 5 December 2006, E.J. Lucas, N.A. Brummitt, O.R. Campos, T.B. Flores & L.R.S. Jennings 1040 (holotype RB!, isotypes BHCB!, CEPEC!, ESA, K, UB). Figures 13, 14 , 15 .

This species is related to Marlierea luschnathiana , from which it is distinguished by its larger petioles (to 18 versus to 8 mm in M. luschnathiana ), narrower blades (to 300 × 70 mm, about four times longer than wide, vs. to 110 × 45 mm, about two times longer than wide), glabrous inflorescences (vs. moderately pilose), flower buds trimerous, the fourth lobe of the calyx resulting from the tearing of the calyx tube (vs. tetramerous) and flowers without petals (vs. with petals).

Tree 1.5– 8 m. Twigs glabrous, grey or brown, sometimes with sparse glands, the internodes 25–70 × 2–3 mm, the bases occasionally with lanceolate cataphylls to 20 × 2.5 mm, these covered with dark glandular dots up to 0.5 mm in diameter and about five per mm 2. Leaves with petioles 7–18 × 1.5–2.5 mm, glabrous, adaxially applanate and sometimes black when dry; blades oblong to lanceolate-oblong, 150–300 × 38–70 mm, glabrous, with glandular dots visible on both sides, more so abaxially, discolorous, adaxially olive-green and dull when dry, abaxially lighter, yellowish to brownish, somewhat shining; glandular dots about 0.5 mm in diameter, up to three per mm 2; apex acute to acuminate in 10–15 mm; base cuneate; midvein plane to prominent adaxially and markedly prominent abaxially; lateral veins 25 to 38 at each side, prominent on both sides, more so abaxially, leaving the midvein at angles about 80°; marginal vein 1.5–2 mm from the slightly revolute margin. Inflorescences paniculiform, the main axis 35–90 × 1–1.5 mm, with triangular, concave bracts to 10 × 3 mm, deciduous, at the base, the first order ramifications 10–40 × 0.5–1 mm, the second order 6–10 × 0.5–1 mm; bracts to 2 × 1 mm, glabrous, triangular and persisting in the axes; bracteoles glabrous, triangular, 1–1.1 × 0.6–1 mm. Flower buds 3–4 x 3 mm, crowned usually by three tumid, slightly cucullate and somewhat unequal calyx lobes, occasionally a fourth one either tumid as the other three but much smaller (see Figure, either resulting from the irregular tearing of the calyx tube; flowers glabrous; calyx lobes tearing irregularly the calyx tube at anthesis, 2.5–3 × 2–2.8 mm; petals not seen in flower buds examined, possibly abortive; stamens mostly fallen in the flowers examined and not counted, 2.5–3 mm, the anthers elliptic, to 0.3 × 0.2 mm, eglandular; staminal ring glabrous, to 2 mm in diameter; calyx tube to 0.8 mm deep; style 6 mm, the stigma papillose; ovary densely wartyglandulose outside, the glands 0.5–0.8 mm in diameter; locules two, with two ovules per locule. Fruits globose, to 20 × 20 mm, densely glandulose, crowned by four lanceolate to oblong pieces of the calyx lobes and part of the calyx tube, unequal in size, 2–3 × 2 mm; one seed, somewhat reniform, 10–12 × 8–10 mm, the testa dark brown, papyraceous, easily detachable; embryo with two foliaceous cotyledons and a hypocotyl surrounding them.

Distribution, habitat and phenology:—This species was collected in the coastal Atlantic rainforests of Bahia, in the municipalities of Arataca, Buerarema, Itacaré, Una and Wenceslau Guimarães, where it grows as a forest tree at altitudes 60–600 elev.; flowers were collected in December and fruits in February, April, May and November.

Conservation:— Myrcia trimera was collected in five southern Bahian municipalities that are not contiguous, the most distant ones located about 150 km from each other, comprising an area of about 8,000 km 2 ( IBGE 2015). Considering this, Myrcia trimera can be scored as Vulnerable (VU), since it fits IUCN criteria B1ab(iii, iv) for this category: the total known extent of occurrence of this species is smaller than 20,000 km 2 (criterion B1) and, although many collections are from protected areas, southern Bahia is presently subject to very intense human occupation and deforestation, what can reduce drastically its habitat (criteria a, b(iii; iv)).

Affinities:—The calyx morphology defines this species as a member of the genus Marlierea Cambessèdes (1832 – 1833: 373); nevertheless, the distinction between Marlierea , with calyx lobes fused in bud, and Myrcia , with calyx lobes separate in bud, is not considered here, since Lucas et al. (2011) demonstrated that most species of Marlierea are nested within a clade comprising several species of Myrcia (“clade 9” in Lucas et al. 2011). Myrcia trimera is apparently related to Marlierea luschnathiana (O.Berg) D.Legrand ( Berg 1857 –1859: 147; Legrand 1962: 33; for description see Berg, under Eugeniopsis luschnathiana ; type image: BR barcode 0000008455932), also collected in Bahia, from which it is kept apart through the characters given in the diagnosis.

Etymology:—The epithet is allusive to the trimerous flower buds; although the epithet may seen elusive because some flowers occasionally bear a fourth calyx lobe resulting from the irregular rupture of the calyx tube, trimerous flowers are the rule, and the singularity of this character is worthy to be stressed.

Paratypes:— BRAZIL. Bahia: mun. Arataca, Serra do Javi , 7 April 1995, L. A. Mattos Silva A. Amorim, E. C. Leme & P. Hahoum 3098 ( CEPEC!) ; mun. Buerarema, Fazenda Santa Rosa , 15 ° 06’19”S, 39°17’20”W, 5 February 2003, P. Fiaschi, J. L. Paixão, S. Sant’Ana & H. Querino 1277 ( BHCB!, CEPEC!, NY) ; idem, rodovia Buerarema—Vila Brasil , km 14, 9 February 1982, A. Carvalho, L. A. Mattos Silva & T. S. Santos 1174 ( CEPEC!, NY) ; mun. Itacaré , ca. 5 km SW of Itacaré, approx. 39°03’W, 14°20’S, 30 March 1974, R. M. Harley 17479 ( ESA, K, NY, RB!, UB) ; idem, estrada Itacaré—Taboquinhas , 20 November 1991, A. Amorim, S. Sant’Ana, T. S. Santos, E. Santos & H. S. Brito 402 ( CEPEC!) ; idem, rodovia BA-654, 14°18’S, 39°02’W, 28 April 1987, L. A. Mattos Silva, T. S. Santos & M. E. Soares 2192 ( CEPEC!) ; mun. Una, ramal km 5 rod. São José—Una , February 1986, T. S. Santos & E. J. Judziewicz 4022 ( CEPEC!) ; idem, Reserva Biológica de Una, Fazenda Piedade , 5 May 2005, J. L. Paixão, M. Pessoa & L. Carlos 397 ( CEPEC!, NY) ; mun. Wenceslau Guimarães, Reserva Estadual de Wenceslau Guimarães , 01 April 1993, S. Sant’Ana & L. A. Mattos Silva 298 ( CEPEC!, NY) .

Figures

FIGURE 14. Myrcia trimera. Open flower, showing calyx morphology (scale: 2 mm; photo by Laura Jennings).

FIGURE 15. Myrcia trimera. Flower buds; from holotype (scale: 10 mm; photo by Laura Jennings).