Myrcia unana Sobral, Faria & Villaroel, 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 : 228

13. Myrcia unana Sobral, Faria & Villaroel , sp. nov. Type:— BRAZIL. Bahia: mun. Una, Reserva Biológica do Mico-Leão ( IBAMA) ; entrada no km 46 da rodovia BA-001 Ilhéus / Una , 15009 ’ S, 39005 ’ W, 23 December 1996, S. C. Sant’Ana, A. Henderson & J. L. da Paixão 631, ( CEPEC!, holotype). Figure 16 .

This species is apparently related to Myrcia maximiliana , but is kept apart from it through its longer petioles (to 15 mm versus up to 6 mm in M. maximiliana ), narrower blades (5–7 times longer than wide vs. up to 3 times longer than wide), and longer calyx lobes (to 10 mm vs. up to 4 mm), these triangular or elliptic (vs. ovate).

Trees 2– 6 m. Twigs terete, densely covered by simple, erect, rufescent trichomes to 2.5 mm, these becoming more scarce with age; internodes 20–50 × 1.5–2 mm, sometimes with linear cataphylls to 8 × 1 mm at its base, abaxially pilose as the twigs. Leaves with petioles as the twigs or glabrescent with age, 10–15 × 1,5– 2 mm, adaxially canaliculate; blades oblong-lanceolate or oblong, 135–180 × 22–33 mm, 5–7 times longer than wide, densely and uniformly rufescent when young, discolorous when dry, the adaxial face dull green, glabrous and sometimes markedly bullate, the abaxial face light brown, uniformly but sparsely covered with trichomes as the twigs, these never concealing the surface and becoming scarce with age; glandular dots 1 to 5 / mm 2, these about 0.1 mm in diameter and visible only through light; apex acute or acuminate to 10 mm; base cuneate; midvein adaxially sulcate and raised abaxially; lateral veins 30 to 35 at each side, raised on both sides, a little more so abaxially, leaving the midvein at angles 70–80°; marginal vein 0.8–1 mm from the margin, the margin itself revolute, in young leaves finely ciliate, the cilia to 2 mm long. Inflorescences at the apex of branches, not subtended by leaves, pilose as the twigs, with one peduncle 10–30 × 1.5 mm, from which two branches 10–25 × 1 mm arise; number of flowers not counted (axes bear between 6 to 15 scars, possibly from flowers); bracts not seen; flowers sessile; bracteoles narrowly triangular, 10–15 × 2.5–4 mm, with trichomes to 1 mm abaxially; flowers not seen, only very young fruits examined; calyx lobes and ovary uniformly covered with rufescent trichomes to 2 mm; calyx lobes five, glabrous adaxially and pilose abaxially, unequal, two small ones triangular, to 6 × 4 mm, the larger ones narrowly triangular or elliptic, to 10 × 5 mm; petals not seen; staminal ring to 4 mm in diameter, glabrous; calyx tube to 1 mm deep, glabrous; stamens not seen; style remnant 7 mm; ovary with three locules (five ovules where observed; one possibly aborted in the fruit examined). Fruits very young, globose to elliptic, to 10 × 8–10 mm, densely pilose; seeds immature, not examined.

Distribution, habitat and phenology:—This species is presently known from four collections from the coastal Bahian municipalities of Ilhéus and Una, where it was collected in rainforests; flowers were collected in February, October and November; immature fruits were collected in November and December.

Conservation:—Considering that the municipalities of Ilhéus and Una, which are contiguous, have been intensely botanically surveyed—27,652 and 18,673 collections respectively ( CRIA 2015) along an area of 2,960 km 2 ( IBGE 2015), with the relatively high average of 15 collections/km²—the scarcity of collections of this species may be suggestive of its rareness. In the light of present information available, we can score this species as Endangered (EN) according to IUCN conservation criteria ( IUCN 2001), since it fits criteria B1ab(iii): its extent of occurrence is smaller than 5,000 km ² (criterion B1) and it grows in a severely fragmented habitat (criterion B1a) what allow a projected reduction of its extent and quality (criterion B1b(iii)).

Affinities:— Myrcia unana is related to M. maximiliana, O.Berg (for description see Berg 1857 –1859: 164; type image: BR barcode 0000008552440, erroneously filed under Myrciaria ), also collected in Ilhéus, from which it is distinguished by the characters given in the diagnosis.

Etymology:—The epithet is allusive to the location of the type collection.

Paratypes:— BRAZIL. Bahia: mun. Ilhéus , ramal da Fazenda Ipiranga a 21 km de Olivença, 25 October 1972, R. S. Pinheiro 1941 ( CEPEC) ; idem, Olivença, estrada Olivença-Buerarema, 37 km do início da estrada não pavimentada em Olivença , 10 February 1994, J. R. Pirani, J. A. Kallunki, I. Cordeiro & P. L. R. Moraes 2916 ( SP, UB!) ; mun. Una, Reserva Biológica do Mico-Leão ( IBDF), km 8 da rodovia Una / Ilhéus (BA-001), 20 November 1987, E. B. dos Santos & M. C. Alves 148 ( CEPEC) .

Figures

FIGURE 16. Myrcia unana. Holotype (scale: 50 mm).