Myrcia venosissima Sobral & P. L. Viana 2016, sp. nov.
Creators: name: Sobral, Marcos
name: Caliari, Cláudia P.
name: Gressler, Eliana
name: Mazine, Fiorella F.
name: Magenta, Mara
name: Viana, Pedro L.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia venosissima

description: 7. Myrcia venosissima Sobral & P.L.Viana, sp. nov.
Type:— BRAZIL. Minas Gerais: mun. Felício dos Santos, APA Felício, trilha para a cachoeira do Sumidouro, 18°13’00”S, 43°15’00”W, 20 May 2007, P.L. Viana, M. Sobral, K. Antunes & H. Bispo 5201 (holotype RB!, isotypes BHCB!, HUFSJ!). Figure 9.
This species is related to Myrcia almasensis, from which it is distinguished by its habit (a shrub to 0.5 m vs. up to 5 m in M. almasensis), its inflorescences with shorter peduncles (to 3 mm vs. up to 10 mm), with 1 to 3 flowers (vs. up to 10 flowers), and its flowers with longer bracteoles (to 5 mm vs. up to 2 mm), longer calyx lobes (to 5 mm vs. to 2 mm) and longer styles (to 7 mm vs. to 1 mm).
Shrub to 0.5 m. Twigs densely covered with white or grey more or less appressed trichomes to 1 mm, falling with age and then the bark brown or grey, rugose; internodes 6–8 × 1–1.5 mm. Leaves with petioles 3–4.5 × 0.6–0.8 mm, canaliculate; young leaves with white trichomes to 0.2 mm, these falling with age; blades elliptic, 13–21 × 8–11 mm, 1.6–2 times longer than wide, strongly discolorous when young, the adaxial side brown or green except for the midvein, which is covered by dense white trichomes to 0.2 mm, the abaxial side white or grey, covered by a dense floccose indumentum, with trichomes to 1 mm; adult leaves with adaxial side mostly glabrous and sometimes shining, occasionally with scattered trichomes along the midvein, and abaxial side with densely appressed trichomes to 0.1 mm; glandular dots visible mostly on the adaxial side, to 0.1 mm in diameter and 7 to 10/mm 2; apex widely acute to rounded; base cuneate; midvein impressed adaxially and raised abaxially; secondary veins 12 to 15 at each side, straight, leaving the midvein at angles about 70°, visible and sometimes clearly prominent on both sides; marginal vein 0.5–0.6 mm from the margin, the margin itself revolute and with a yellow or brown ridge about 0.1 mm thick. Flowers axillary, sessile or with pedicels to 2 × 1 mm, solitary or up to three crowded at the apex of axillary peduncles 2–3 × 1–1.5 mm; bracts narrowly triangular, to 5.5 × 2 mm, apparently persisting at anthesis, adaxially glabrous and abaxially covered with trichomes to 0.2 mm; bracteoles narrowly triangular, to 5 × 1.2 mm, pilose as the bracts and apparently also persisting after anthesis, with up to four linear white colleters to 0.2 × 0.02 mm at the base of the adaxial side; flower buds elliptic, 4–5 × 3–3.5 mm, densely covered with white or grey trichomes to 0.2 mm; calyx lobes five, more or less equal between them, narrowly triangular, 3.5–5 × 2–2.5 mm, adaxially glabrous and abaxially with trichomes to 0.2 mm; petals white, elliptic, concave, 4 × 2.5–3 mm, glabrous; stamens about 120, filaments 4–6 mm, anthers elliptic, to 0.4 × 0.2 mm, eglandular; staminal ring to 3 mm wide, with scattered trichomes to 0.2 mm; calyx tube 0.5 mm deep; style 6–7 mm, glabrous, the stigma punctiform and minutely papillose; ovary with three locules and two ovules per locule. Fruits not seen.
Distribution, habitat and phenology:—This species is presently known only from the municipality of Felício dos Santos, in the central portion of the state of Minas Gerais, where it grows in rocky fields along the Espinhaço Range, at altitudes about 1,300 m elev.; flowers were collected in June.
Conservation status:—This species is presently known from two gatherings from Felício dos Santos, a municipality with 358 km 2 (IBGE 2015b). Considering that this area is scarcely surveyed—there are presently only 314 collections from there (CRIA 2015), with an average of 0.9 collection/km²—and there is no additional information about the distribution of this species, it seems adequate to score it as DD (Data Deficient) according to IUCN criteria (IUCN 2001).
Affinities:— Myrcia venosissima is apparently related to the Bahian endemic M. almasensis Nic Lughadha (1994: 323; type image: K barcode 000332041), with which it shares the markedly reticulate leaves and ovaries with three locules, but is distinguished by the characters given in the diagnosis. This species probably matches those of informal “group 6” in the phylogenetic scheme of Lucas et al. (2011) due to its trilocular ovary; nervertheless, a very characteristic feature of this group, that is the presence of nearly one gland per areole in the blades, was not observed in M. venosissima.
Etymology:—The epithet means “very venose” in Latin, alluding to the dense venation of the leaves of the species.
Paratype:— BRAZIL. Minas Gerais: mun. Felício dos Santos, APA Felício–Cachoeira do Sumidouro, 18013 ’00’’ S, 43015 ’00’’ W, 10 Jun. 2006, P.L. Viana, F.S.F. Leite, L.E. Lopes & M. Ferreira 251 5 (BHCB!).
description: Published as part of Sobral, Marcos, Caliari, Cláudia P., Gressler, Eliana, Mazine, Fiorella F., Magenta, Mara & Viana, Pedro L., 2016, Seven new southeastern Brazilian species of Myrcia (Myrtaceae), pp. 27-44 in Phytotaxa 247 (1) on pages 41-42, DOI: 10.11646/phytotaxa.247.1.2, http://zenodo.org/record/13676381