Myrcia macucana Sobral, 2017

Sobral, Marcos, Costa, Idimá G., Souza, Marcelo C. & Zorzanelli, João Paulo F., 2017, Five new species and one new combination in Brazilian Myrtaceae, Phytotaxa 307 (4), pp. 233-244 : 243

5. Myrcia macucana Sobral , sp. nov.

Type:— BRAZIL. Minas Gerais: Timóteo; Macuco, Parque Estadual do Rio Doce , 19 o 35’28”S, 42 o 34’07”W, 3 March 2004, G.S. França & F. Rage 489 (holotype BHCB! ; isotype HUFSJ! ).

Figure 5 .

Diagnosis:—This species is related to Calyptranthes anceps , differing by its discolorous blades with the midvein consistently impressed adaxially (vs. concolorous blades with moderately biconvex at least along the proximal half adaxially in C. anceps ), shorter inflorescences (to 25 mm, the peduncle to 10 mm, vs. to 100 mm, the peduncle to 70 mm) and pilose flowers (vs. glabrous).

Description:—Shrub to 1.5 m. Twigs glabrous or with very scattered simple trichomes to 0.2 mm; internodes 25– 45 × 2 mm, moderately longitudinally striate. Leaves with petioles 8–11 × 1.8–2 mm, glabrous, adaxially canaliculate; blades oblong or lanceolate, 140–190 × 40–50 mm, 3.5–3.8 times longer than wide, discolorous when dry, dull green adaxially and light brown abaxially, glabrous adaxially and abaxially with very scattered brown or grey asymmetrically dibrachiate trichomes to 0.1 mm; glandular dots 5 to 8/mm², 0.1–0.2 mm in diameter, visible abaxially, scarcely visible when backlit; base cuneate; apex acuminate to 8 mm; midvein finely impressed adaxially and strongly raised abaxially; lateral veins 20 to 25 at each side, raised on both sides, more so abaxially; marginal veins two, the inner one 2–3 mm from the margin, the outer one very faint, to 1 mm from the margin, the margin itself with a light brown girdle to 0.2 mm wide. Inflorescences axillary or terminal, paniculiform, triangular in profile, 15–25 × 1.5–2 mm, with triangular-linear deciduous bracts 4–20 × 2–3 mm at the base, the peduncle 5–10 mm until the first ramification, the axis applanate and mostly glabrous, occasionally with trichomes as the twigs, with one or two branches along the axis, these 2–4 mm and subtended by deciduous triangular bracts to 2 × 1 mm; flowers 30 to 40, mostly in triads at the tip of the branches; bracteoles triangular, deciduous at anthesis, to 1.5 × 0.5 mm; flower buds obovate, 3–4.5 × 1–2 mm, uniformly and moderately covered with brown symmetrical dibrachiate trichomes to 0.2 mm; calyx lobes fused in a calyptra, this 1.5–2 × 1.5 mm, the apex apiculate in 0.5–0.6 mm; petals absent or up to two in the flowers examined, spathulate or obovate, 1.5–2 × 0.5–0.8 mm; stamens ca. 60, 4–6 mm, the anthers globose, 0.2–0.3 mm in diameter, eglandular; staminal ring to 1.5 mm in diameter; calyx tube to 2 mm deep; style 6.5–7 mm, the stigma punctiform and papillose; ovary with two locules and two ovules with central-basal placentation per locule. Fruits not seen.

Distribution, habitat and phenology:—Presently known only from the type collection, from rainforests at Rio Doce State Park in the municipality of Timóteo, eastern Minas Gerais, at about 250 m elev.; flowers were collected in March.

Conservation:—Considering that Myrcia macucana is known only from the type specimen, it seems adequate to consider it as DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2001).

Affinities:—Apparently close to Calyptranthes anceps O.Berg ( Berg 1857 –1859: 40; type image: BR 000000855179), a species presently known from Rio de Janeiro, from which it is distinguished by the characters cited in the diagnosis. For discussion about the nomenclatural question on Calyptranthes and Myrcia , see comments under Myrcia fria .

Etymology:—The epithet refers to the collection site, Fazenda do Macuco.

Figures

FIGURE 5. Myrcia macucana. Isotype at HUFSJ (scale = 50 mm).