Myrcia parca Sobral, 2016

Sobral, Marcos, Caliari, Cláudia P., Gressler, Eliana, Mazine, Fiorella F., Magenta, Mara & Viana, Pedro L., 2016, Seven new southeastern Brazilian species of Myrcia (Myrtaceae), Phytotaxa 247 (1), pp. 27-44 : 34-36

4. Myrcia parca Sobral , sp. nov.

Type:— BRAZIL. Espírito Santo: mun. Viana, arredores da Rebio São Paulo Viana, propriedade do sr. Valtinho , 20º18’23” S, 40º32’30” W, 700 m, 19 January 2009, L. Kollmann, A.P. Fontana, R. Goldenberg & R. Forzza 11477 (holotype RB! ; isotypes BHCB , CEPEC , MBML , UPCB ). Figure 5 .

This species is apparently related to Myrcia warmingiana , from which it is distinguished through its concolorous blades (versus markedly discolorous in M. warmingiana ), up to three times longer than wide (vs. 2.6–2.8), with up to 30 lateral veins (vs. less than 20), one marginal vein (vs. two), glabrous adult blades (vs. pilose), inflorescences triflorous (vs. with 5 or more flowers) sepals to 1 mm (vs. to 2 mm) and ovary smooth (vs. longitudinally 10–ridged); it may also remind Myrcia curtipendula , from which it can be distinguished mostly by the erect inflorescences (versus pendulous in M. curtipendula ) with applanate axis to 1.7 mm wide (vs. rounded, to 0.7 mm wide) with up to three flowers (vs. up to 10 flowers), the ratio of the inflorescence axis to the pedicels of the lateral flowers 10–14:1 (vs. 2–3.5:1), the obovate flower buds (vs. globose) and the ovaries densely pilose, clearly distinct from the calyx lobes (vs. glabrous or sparsely pilose, not contrasting with the calyx lobes).

Tree to 7 m. Plants glabrous except for the flowers and very young leaves. Twigs brown, terete; internodes 20–30 × 1–2 mm. Leaves when young covered with simple grey trichomes to 0.1 mm, these falling entirely in adult ones; petioles 7–10 × 0.8–1 mm, adaxially canaliculate, about the same color as the blades when dry; blades narrowly elliptic, 95–135 × 27–40 mm, 3.2–4 times longer than wide, concolorous or weakly discolorous, then lighter abaxially, when dry; glandular dots to 10/mm², about 0.1 mm in diameter, moderately visible on both faces; apex acuminate in 18–24 mm; base cuneate; midvein finely impressed adaxially and moderately raised abaxially; lateral veins to 30 at each side, leaving the midvein at angles about 80°, visible and moderately raised on both sides, a little more so abaxially, intermixed with secondary lateral veins sometimes about the same gauge; marginal vein 0.8–0.9 mm from the margin, the margin itself plain. Inflorescences axillary or at the apex of branches and not subtended by leaves, triflorous, the flowers at the end of an applanate axis 30–44 × 1–1.8 mm, the apical flower sessile, the lateral flowers with pedicels up to 3 × 0.6 mm; bracts not seen, deciduous before anthesis, leaving visible scars, these with about ten linear colleters to 0.3 mm; bracteoles not seen, deciduous before anthesis and leaving visible scars; flower buds obovate, 5–6.5 × 3–4 mm, the ovary densely covered with simple white, appressed trichomes to 0.1 mm, clearly distinct from the glabrous or less pilose calyx lobes, these five, slightly unequal between them, some rounded and others rounded and very minutely apiculate, 0.8–1 × 2 mm, with scattered trichomes as the ovary adaxially or on both sides; petals five, white, elliptic, 4 × 2.5–3 mm; stamens not counted, filaments to 5 mm, the anthers elliptic, to 0.6 × 0.3 mm, with one apical gland and thecae slightly displaced in distinct levels; staminal ring to 2 mm in diameter, with scattered trichomes; calyx tube to 1 mm deep, with scattered trichomes; style to 9 mm, the stigma slightly capitate and finely papillose; ovary bilocular, with two ovules per locule. Fruits unknown.

Distribution, habitat and phenology:—This species is presently known only from the type collection, from montane rainforests of the municipality of Viana, in the state of Espírito Santo, at about 700 m elev.; flowers were collected in January.

Conservation:—The municipality of Viana has an area of 312 km ² from which are known 560 gatherings, with an average of 1.8 collection/km², a moderate sampling effort. Considering this, the fact of this species being known for only one collection may be an indicative of its relative rareness; additionally, the small area of the municipality, if considered as a proxy of the species’ extent of occurrence, would be also suggestive of an endangered status ( IUCN 2001). Nevertheless, since no additional information on the environmental conditions of the collection site are known, it seems adequate to score this species as DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2001).

Affinities:—This species also has characters that allow to assign it to the informal “group 3” proposed by Lucas et al. (2011), which encompasses the species with sinuose opening of anthers formerly assigned to the Bergian genus Gomidesia ( Berg 1855 –1856: 6); Myrcia parca is apparently related to Myrcia warmingiana Kiaerskou (1893: 104 ; type image: P barcode 02273024), from the neighboring state of Rio de Janeiro, and can also remind Myrcia curtipendula Nic Lughadha ( Nic Lughadha et al. 2010: 21; type image: K barcode 000331907) also collected in Espírito Santo, but is distinguished from them through the characters given in the diagnosis.

Etymology:—The epithet is derived from the Latin word for “sparing” or “not frequent”, alluding to the paucity of flowers of the inflorescences.

Figures

FIGURE 5. Myrcia parca—holotype. Insert: inflorescences (scale: 10 mm).