Myrcia monoclada Sobral 2013, sp. nov.
Creators: name: Sobral, Marcos
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Plantae
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia monoclada

description: 1.7. Myrcia monoclada sp. nov.
Type: BRAZIL. Bahia: mun. Una, 20 km N along road from Una to Ilhéus, 39 o 02´W, 15 o 11´S, 23 jan. 1977, R. Harley 18204 (holotype CEPEC; isotype K).
Figure 7.
This species is related to Myrcia riodocensis, but is distinguished by the larger leaves and pentamerous flowers.
Tree to 5 m, unbranched. Internodes 20–50 × 7 mm, glabrous. Leaves with petioles to 3 × 4 mm, visible abaxially, glabrous; blades ovate-lanceolate, 180–220 × 70–75 mm, 2.5–3 times longer than wide, concolorous when dry, glabrous, with about ten glandular dots per square milimeter, these smaller than 0.1 mm in diameter, faintly visible on both surfaces; apex acute to obtuse; base cordiform; midvein plane or moderately sulcate adaxially, strongly prominent and darker than the surface abaxially; lateral veins 25 to 30, visible on both sides and prominent abaxially, leaving the midvein at angles of 70–80 degrees, secondary lateral veins sometimes visible abaxially; marginal vein 2.5–3 mm from the margin, occasionally a second vein visible about 0.8 mm from the margin, the margin itself with a darker girdle about 0.3 mm wide. Inflorescences axillary, paniculiform, up to four times ramified, uniformly covered with appressed dibrachiate trichomes to 0.2 mm, the main axis 90–200 × 2–4 mm, sometimes abortive, to 10 × 3 mm, the secondary axes to 90 × 2 mm; bracts not seen; flowers sessile or with "pedicels" (indeed the last level of branching) to 1 × 0.5 mm; bracteoles not seen, deciduous before anthesis and leaving visible scars at the base of flower buds, these obovate, 2–2.8 × 2 mm, glabrous or with scattered white dibrachiate trichomes to 0.2 mm, these more dense proximally; calyx lobes five, widely ovate, glabrous on both sides, somewhat unequal in size, 0.4–0.8 × 0.8– 1.2 mm, patent at anthesis; petals five, rosy, orbicular, glabrous and with scattered glandular dots, 1.8–2 mm in diameter; stamens about fifty, 2–3 mm, the anthers globose, to 0.2 × 0.2 mm, eglandular; staminal ring glabrous, to 2 mm in diameter; calyx tube 0.5–1 mm deep, glabrous; style 3–4 mm, the stigma punctiform and minutely papillose; ovary with three locules and two ovules per locule. Fruits not seen.
Distribution, habitat and phenology:—presently known only from the municipality of Una, in southern Bahia, where it was collected in forests at about 100 m elev.; flowering material was colleted in January.
Conservation:—the municipality of Una was intensely surveyed botanically – about 9,000 collections (CRIA 2012) within an area of 1,200 km 2 (IBGE 2012), with an average of 7.5 collections /km 2. In light of this information the existence of only one gathering of M. monoclada is strongly suggestive of its rarity. Since additional information on environmental status such as habitat fragmentation and decline are wanting, however, it must be scored as DD (Data Deficient), according to IUCN criteria (IUCN 2001).
Affinities:—this species is realted to Myrcia riodocensis G.M.Barroso & Peixoto (for description see Barroso & Peixoto 1990), from which it is kept apart by the characters in the following key:
1. Leaves with evident petioles to 2 mm; blades to 140 × 45 mm, the base obtuse; flowers tetramerous ......................... ......................................................................................................................................................... Myrcia riodocensis
—. Leaves with petioles to 3 mm, visible only abaxially; blades to 220 × 75 mm, the base cordiform; flowers pentamerous. .................................................................................................................................................. Myrcia monoclada
Etymology:—from the Greek words for “with only one branch", alluding to the unbranching habit of the type material, as registered in the collection label.
description: Published as part of Sobral, Marcos, 2013, Eight New Atlantic Rainforest Species and Nomenclatural Notes in Brazilian Myrtaceae, pp. 43-61 in Phytotaxa 135 (1) on pages 55-57, DOI: 10.11646/phytotaxa.135.1.6, http://zenodo.org/record/5086159