Eugenia rara Rigueira & 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 : 213-214

6. Eugenia rara Rigueira & Sobral , sp. nov. Type: BRAZIL, Bahia, mun. Itamaraju , 10 April 2011, D. Rigueira et al. 16 (holotype ALCB!; isotype HUFSJ!). Figure 7 .

This species is apparently related to Eugenia subterminalis , from which it is distinguished through its larger leaves (up to 80 mm versus up to 50 mm in E. subterminalis ) with visible venation (vs. venation inconspicuous) and flowers pilose (vs. glabrous), apiculate (vs. not apiculate) with fused calyx opening irregularly (vs. calyces tearing in four subequal calyx lobes).

Tree to 13 m. Twigs glabrous, terete, internodes 20–35 × 0.5–0.6 mm. Leaves with petioles 3–6 × 0.3–0.6 mm; blades elliptic or lanceolate, 55–80 × 16–24 mm,3–3.5 times longer than wide, glabrous or with scattered simple white trichomes to 0, 1 mm, discolorous, lighter abaxially; apex acuminate in 5–6 mm; base cuneate; glandular dots smaller than 0.1 mm in diameter, 6 to 10/mm², visible abaxially; midvein moderately raised adaxially, more strongly so abaxially; lateral veins 10 to 12 at each side, leaving the midvein at angles 60–70º, slightly raised adaxially and visibly so abaxially; marginal vein 1–2.1 mm from the margin, sometimes a second vein 0.5 mm from the margin, the margin itself with a yellow girdle 0.2 mm wide and undulate when dry. Inflorescences terminal, racemiform, the axis to 2 × 0.5 mm, with up to six flowers, the axis and the pedicels densely covered with simple white trichomes to 0.1 mm; bracts hemispheric, glabrous, to 0.5 × 0.2 mm; pedicels to 3 × 0.2 mm; bracteoles elliptic, 0.3–0.8 × 0.1–0.2 mm; flower buds globose or obovate, 4–5 × 3–3.5 mm, densely and uniformly covered by appressed grey trichomes to 0.1 mm, apically with a mucron to 0.5 mm; calyx lobes completely fused and opening lines not evident, tearing irregularly in two to four lobes, one of them occasionally larger and resembling a calyptra; petals four, rounded, glabrous, 4 × 3–3.5 mm; stamens about 100, to 4 mm, the anthers globose, 0.3 × 0.3 mm, eglandular; staminal ring 3 mm in diameter, glabrous; calyx tube absent or to 0.5 mm deep; style 3 mm, the stigma punctiform; ovary with two locules and 10 to 15 centrally attached ovules per locule. Fruits not seen.

Distribution, habitat and phenology:—This species is presently known only from the type collection, from coastal atlantic rainforests in the municipality of Itamaraju; flowers were collected in April.

Conservation:—The municipality of Itamaraju has an area of 2,215 km ² ( IBGE 2015), from which there are registered 2,114 gatherings ( CRIA 2015), summing about one collection/km², a minimum gathering effort. Although the area of the municipality is suggestive of an endangered (EN) status according to IUCN conservation criteria ( IUCN 2001), there is no additional information about the habitat of the species. Therefore, present information allows scoring this species as DD (Data Deficient) according to IUCN criteria.

Affinities:—The singular opening of the calyx of this species, with one calyx lobe sometimes resembling a calyptra, was not registered for species of the genus Eugenia ; one should point that this calyx morphology reminds that of the genus Neomitranthes Kausel ex D.Legrand ( Legrand & Klein 1977: 671) , what is a plausible possibility. Nevertheless, as usually occurs in American Myrtaceae , the most distinctive character of Neomitranthes and Eugenia is seed morphology (for details see Landrum & Kawasaki 1997: 523); since fruits are not known, a definitive choice is not possible. On the other side, the number of ovules in each locule (up to 15) is usual in Eugenia , but not registered for Neomitranthes (with up to 6 ovules per locule; see Landrum & Kawasaki 1997: 529), a character that, although ancillary, is helpful and directed our choice for this genus. Eugenia rara is apparently related to Eugenia subterminalis De Candolle (1828: 263 ; no type images available online), from which it is distinguished through the characters given in the diagnosis; considering this affinity, this species will probably fit in clade 7 of the phylogenetic scheme for Eugenia proposed by Mazine et al. (2014), due to the presence of completely fused calyx lobes.

Etymology:—The epithet is allusive to the rare characters of the flowers for the genus Eugenia , which present closed calyces with an evident apiculum.

Figures

FIGURE 7. Eugenia rara. Holotype (scale: 50 mm). Insert: flowers (scale: 10 mm).