Myrcia cataphyllata M.F.Santos, 2015

Santos, Matheus F., Lucas, Eve, Sobral, Marcos & Sano, Paulo T., 2015, New species of Myrcia s. l. (Myrtaceae) from Campo Rupestre, Atlantic Forest and Amazon Forest, Phytotaxa 222 (2), pp. 100-110 : 101-103

1. Myrcia cataphyllata M.F.Santos , sp. nov. ( Figs. 1A–E , 2 )

Myrcia cataphyllata is related to Myrcia bicolor Kiaerskou (1893:65) , but differs in its keeled immature branches (vs. not keeled), cataphylls 1.5–1.7 cm long and not early deciduous (vs. 0.1–0.7 cm and early deciduous), persistent or late deciduous bracts (vs. early deciduous) and calyx lobes with acuminate or aristate apices (vs. rounded).

Type:— BRAZIL. Bahia: mun. Una, Reserva Biológica de Una, entrada no km 46 da Rod. BA 001 Ilheus/Una, coletas efetuadas a ca. 10 km no ramal de acesso ao Ecoparque de Una, 15°09’S, 39°05’W, 30 April 2000 (fr.), S.C.Sant’Ana 782 (holotype CEPEC!, isotype SP!).

Shrub to 2 m high. Immature parts with epidermal peeling; trichome ferruginous or brown, 0.1–0.3 mm long, dibrachiate. Twig when immature reddish, flattened, keeled; greyish at maturity, cylindrical, cortex slightly cracked, glabrescent to glabrous; branching sympodial, 1–2 branches per node, epidermal protrusion present at the internodes, internode 2.7–6.2 cm long; cataphyll foliaceous, 15.0–17.0 × 3.0–4.0 mm, at all internodes, persistent or late deciduous, free, lanceolate, externally with scattered trichomes to glabrous, internally glabrous. Leaf concolorous, coriaceous, blade 9.9–18.2 × 2.6–6.0 cm, narrowly elliptic, elliptic or obovate, apex acuminate or acute, base narrowly cuneate or cuneate, margin plane, secondary veins 3–9 mm apart, held at an angle of 35–70° relative to the midvein, one or two marginal veins, the first 1.5–3.5 mm and the second 0.5–1.0 mm from the margin, tertiary veins conspicuous; mature adaxial surface glabrous, midvein sulcate in the first half and flat in the second half, secondary veins prominent or inconspicuous, pellucid gland dots slightly conspicuous, less than 5 per mm 2; mature abaxial surface glabrescent to glabrous, midvein prominent, secondary veins prominent, pellucid gland dots inconspicuous, less than 5 per mm 2; petiole 3.0–7.0 × 2.0 mm, canaliculate, glabrous at maturity. Panicle 4.0 × 6.0 cm, pyramidal, terminal axillary, rachis puberulent to glabrous, 1–2 branching at the base, first internode of central rachis 2.0–3.0 mm wide, semi-cylindrical to flattened, distal internodes flattened, branching opposite, three branches per node, epidermal protrusion present at the internode, usually absent at the apical branches; pairs of bracts at the base of the inflorescence, 0.6–1.8 × 0.1–0.2 cm, lanceolate, externally puberulent to glabrous, internally with scattered trichomes to glabrous, apex acuminate, concave. Bract 8.0–10.0 × 2.0 mm, persistent, lanceolate, folded, apex acuminate, base truncate, adaxial surface glabrous, abaxial surface puberulent. Pedicel not seen. Bracteole 7.0 × 2.0 mm, deciduous, lanceolate, folded, apex acuminate, base truncate, adaxial surface glabrous, abaxial surface puberulent. Floral bud not seen. Hypanthium not tearing at anthesis, externally puberulent, internally glabrous; calyx 5-merous, lobes 1.4–2.5 × 1.2–1.5 mm, distinct from the hypanthium, external lobes smaller than internal lobes, deciduous, widely depressed ovate or triangular, concave, apex acuminate or aristate, base truncate, externally puberulent, internally puberulent or with scattered trichomes; petals not seen; staminal ring glabrous, stamens not seen; ovary not seen, style 1.1 mm long, glabrous, stigma punctiform, papillose. Fruit green when immature, 10.0–12.0 × 11.0–12.0 mm, depressed globose or globose, base attenuate, glabrous, pellucid gland dots covering whole surface, remnants of calyx lobes present or not; seeds not seen.

Distribution and Habitat:— Myrcia cataphyllata occurs in the Atlantic Forest, in the understory of lowland rainforest. It is apparently a rare species, recorded only from the municipality of Una (Bahia state).

Phenology:— Myrcia cataphyllata was collected in fruit in February and April. Flowering material has not been seen.

Etymology:—The specific epithet refers to the cataphylls near the bases of the branchlets, more persistent in Myrcia cataphyllata than in other species of the clade 7 ( sensu Lucas et al. 2011 , Santos 2014; see discussion below).

Conservation status:— Myrcia cataphyllata was recorded from just three localities in the municipality of Una, totalling an area of occurrence smaller than 5,000 km 2. One record is from within the Reserva Biológica de Una, an IUCN category 1A reserve ( IUCN 2013), but even this area is subject to destructive anthropogenic activities such as logging ( Landau et al. 2008). Myrcia cataphyllata was not found during targeted field work in the region suggesting a small population size. This new species is therefore here classified as Endangered (EN, criteria B1a, biii; IUCN 2001).

Discussion:— Myrcia cataphyllata is characterized by keeled branches, unusually big and persistent cataphylls, persistent bracts and calyx lobes with acuminate or aristate apices. Myrcia bicolor also occurs in the region where M. cataphyllata is endemic, but the latter species is readily distinct by the characteristics cited above.

The species belongs to the clade 7 ( sensu Lucas et al. 2011 , Santos 2014).Among the diagnostic characters of this group are dibrachiate trichomes, cataphylls close to the base of internodes, inflorescences with sympodial branching at the base, opposite apical branching, the hypanthium not tearing vertically at anthesis, calyx lobes distinct from the hypanthium, free from each other and deciduous at anthesis. Myrcia cataphyllata possesses all of these characteristics.

Paratypes:— BRAZIL. Bahia: mun. Una , 100 m, 30 April 1981 (fr.), S.A.Mori 13851 (CEPEC!, NY!) ; 18 February 1998 (fr.), T.G.Bacelar 26 ( CEPEC!) .

Figures

FIGURE 1. Myrcia cataphyllata. A. habit. B. twig with persistent cataphyll. C. abaxial surface of leaf blade. D. detail of persistent bracts in the inflorescence rachis. E. fruit with remnants of calyx lobes. Myrcia elevata. F. habit. G. detail of the inflorescence. H. floral bud. I. flower after anthesis (top view). J. cross section of the costate ovary. Vouchers: A–E. Sant’Ana 782 (CEPEC); F–H and J. Prance 8260 (INPA); I. Prance 9001 (INPA).

FIGURE 2. Distribution map of the new species. Myrcia cataphyllata=triangle; Myrcia elevata=circle; Myrcia megaphylla=square; Myrcia sessilissima=diamond.