Myrcia guarujana Sobral, Magenta & Caliari, 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 : 32-34

3. Myrcia guarujana Sobral, Magenta & Caliari , sp. nov.

Type:— BRAZIL. São Paulo: mun. Guarujá, Serra do Guararu, loteamento Ipiranga , área C, P19, árvore 1087, 16 April 2013, M. Magenta, P.S.P. Sampaio & J.M. Santos 883 (holotype RB !, isotypes ESA! , HUSC! ). Figure 4 .

This species is apparently related to Myrcia colpodes , from which it is kept apart through its longer blades (to 300 mm versus 230 mm in M. colpodes ), its densely pilose flowers (vs. glabrous) with calyx lobes to 7 mm (vs. 2 mm) and ovaries with three locules (vs. two).

Tree to 5 m. Twigs densely pilose when young, the trichomes brown and simple, to 3 mm, falling with age; internodes 15–60 × 4–5 mm. Leaves with petioles 4–5 × 2.8–3 mm, subterete and with scattered trichomes; blades markedly bullate, narrowly lanceolate to oblong, 160–305 × 50–64 mm, 4–5.5 times longer than wide, discolorous, lighter abaxially, glabrous and somewhat shining adaxially, sparsely pilose abaxially, the trichomes more dense along the midvein; glandular dots about 0.1 mm in diameter, up to 4/mm²; apex acuminate to 15–20 mm; base cordate; midvein impressed adaxially and strongly raised abaxially; lateral veins 15 to 20 at each side, leaving the midvein at angles of 70–80º, impressed adaxially and raised abaxially; marginal veins two, 3–4 and 0.5–1 mm from the margin, raised on both sides, the margin itself strongly recurved, with a yellow girdle to 0.2 mm wide. Inflorescences axillary or at the apex of branches, not subtended by leaves, paniculiform, up to two times branched, the main axis to 200 × 2 mm, with 20 to 30 flowers, the peduncle to 100 × 2 mm, the first branches two or three pairs, the proximal ones to 20 mm and the distal ones to 5 mm, the axes with trichomes as the twigs; bracts not seen, possibly deciduous before anthesis; flowers sessile; bracteoles not seen, possibly deciduous before anthesis; flower buds globose to obovate, 9–10 × 5–7 mm, uniformly and densely covered with brown trichomes to 1.5 mm, globose, sometimes slightly constricted above the ovary; calyx lobes five, ovate-triangular, glabrous internally, slighlty unequal in size between them, 4–7 × 4–5 mm; petals five, rounded, 5–6 × 6 mm, glabrous adaxially and pilose abaxially; stamens about 100, filaments 6–7 mm, the anthers globose, to 0.4 × 0.4 mm, eglandular; staminal ring ca. 5 mm in diameter, glabrous; calyx tube to 2 mm deep, glabrous; style 8–9 mm, the stigma punctiform and minutely papillose; ovary with three locules and two ovules per locule. Fruits not seen.

Distribution, habitat, phenology:—This species is presently known from the type, collected in rainforest in an urban area of the municipality of Guarujá, in the coastal zone of the state of São Paulo; flowers were collected in April.

Conservation:—The municipality of Guarujá has an area of 143 km ² ( IBGE 2015b), and there are registered about 1,200 collections from there ( CRIA 2015), with an average of 8.3 collections/km², what can be considered a reasonable sampling effort. Considering this, the fact that Myrcia guarujana is known for only one collection may be an indicative of its rareness. Nevertheless, in the absence of additional information, we score this species as DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2001).

Affinities:—In their phylogenetic study of Myrcia s.l. Lucas et al. (2011) associated the presence of trilocular ovaries to three clades, informally named groups 3, 4 and 6, respectively characterized, among other features, by anthers opening through asymmetrical slits, thin staminal ring and blades with one gland per areole. In spite of the trilocular ovary, Myrcia guarujana does not seem to match the characters of any of these groups. On the other hand, it is morphologically close to Myrcia colpodes Kiaerskou (1893: 80 ; type image: P barcode 00161301), a species presently known only from the type specimen, collected in Rio de Janeiro by Auguste Glaziou in 1862, with which it is compared in the diagnosis. Myrcia colpodes is a species with bilocular ovaries and developed calyx tube that matches the characters of “group 9” of Lucas et al. (2011), which comprises the species formally included in the Bergian genus Aulomyrcia ( Berg 1855 –1856: 35).

Etymology:—The epithet is allusive to the municipality where the type was collected.

Figures

FIGURE 4. Myrcia guarujana—holotype (scale: 50 mm). Insert: flower bud (scale: 10 mm).