Miconia valentinensis Bacci & R.Goldenb., 2015

Bacci, Lucas F. & Goldenberg, Renato, 2015, Miconia valentinensis (Melastomataceae), a new species from Espírito Santo, Brazil, Phytotaxa 195 (4), pp. 272-278 : 273-275

Miconia valentinensis Bacci & R.Goldenb. , sp. nov. ( Figs 1A – 2 )

Diagnosis: — Miconia valentinensis can be recognized by the leaves with slightly cordate base, 5+2 nerves (one strongly suprabasal inner pair, plus a basal median pair and a faint additional marginal pair), branches with prominent longitudinal ridges, early caducous calyx with the petals basally adhered to it (the petals still attached to the calyx tube when it falls, after anthesis), anthers dehiscing through a broad longitudinal slit, and by the ovary with a glabrous apex.

Type: –– BRAZIL. Espírito Santo: Iúna, Serra do Valentim , 20º22’50.1”S, 41º27’59”W, 1424 m, 12 April 2014 (fl.), L. Bacci & J. P. F. Zorzanelli 129 (Holotype: UPCB!; Isotypes: HUFU!, K!, MBM!, MBML!, NY!, RB!, VIES!). Trees 8–10 m tall. Branches decorticant, strongly decussate-flattened, (the section 4–5 x 1.5–2 mm), with two prominent, opposite longitudinal ridges 1.5–3 cm long, running through the central portion of the flattened surface of the branch, each beginning and fading between consecutive nodes, moderately covered with sessile, short dendritic trichomes (following Wurdack 1986) ca. 0.1 mm diam., these more dense on the nodes. Leaves opposite ; petioles short, 2.5–4 mm long; blades 4.6–11.2 x 2.2–3.5 cm, slightly discolorous, ovate-elliptic to lanceolate-elliptic, apex acuminate to caudate, base slightly cordate, margins denticulate, membranous when young, later chartaceous, longitudinal nerves 5+2, the inner pair strongly suprabasal joining the midrib by membranes that form pocket domatia in each leaf (0.6–1 cm above the base), the median pair basal, and a marginal pair faint, less conspicuous pair; adaxial and abaxial surfaces moderately covered with caducous, sessile, short dendritic trichomes, more dense on the nerves. Panicles 6.2–9.5 x 4.5–7 cm, terminal, with three main axes departing from the same point at the base of the inflorescence, axes densely covered with sessile, short dendritic trichomes. Flowers 5-merous. Hypanthium 1.8–2 x 1.4–1.8 mm, campanulate, adaxially glabrous, abaxially densely covered with sessile, short dendritic trichomes. Calyx early caducous with the petals basally adhered to it (the petals still adhered to the calyx when it falls, right after anthesis), adaxially glabrous, abaxially with trichomes similar to the ones on the hypanthium; tube ca. 0.3 mm long; calyx lobes 0.5–0.7 mm long, widely triangular, margins entire, apex acute or rounded; calyx teeth ca. 0.4 mm long, acute, attached to the median portion of the abaxial surface of the calyx lobes, equaling or a little longer than the calyx lobes at the top. Petals 1.5–2 x 1–1.2 mm, white, deflexed, ovate, apex asymmetrically emarginate, margins entire, both surfaces papillose. Stamens 10, white, turning brownish in older flowers, isomorphic; filaments ca. 2 mm long, glabrous; connectives up to 0.2 mm prolonged below the thecae, unappendaged; anthers 1.8–2 mm long, oblong and dorsally arched, dehiscing through a large slit comprising the whole length of the thecae. Ovary ca. 0.5 mm long, 2/3 adherent to the hypanthium, 2-locular, apex glabrous; style 3–3.2 mm long, straight, slightly clavate, glabrous; stigma flat. Fruits globose, green when immature (mature not seen), ca. 3.5 x 3 mm; seeds 2–3 per fruit, ca. 2.5 x 1.8 mm, obpyramidal, the raphal zone completely covering one side, testa smooth.

Distribution, ecology and phenology: —At the moment, Miconia valentinensis is known only from the Municipality of Iúna, at the Serra do Valentim, state of Espírito Santo, Brazil, at 1400–1600 m elevation. It was collected next to a road that leads to a peak with a large telecommunications antenna on its top, in a hillside disturbed forest. According to IUCN (2010), M. valentinensis fits into the “critically endangered” category (CR), because the species has been found only in one location. This area was recently considered as a high biological relevance area, with priority for biodiversity conservation ( Ministério do Meio Ambiente 2008), but insofar belongs to a few private owners. Collected with flowers in April, and with young fruits in May and July.

Etymology: —The epithet refers to Serra do Valentim, the only locality where this species has been collected.

Additional specimens examined (paratypes):— Brazil. Espírito Santo: Serra do Valentim , 28.IV.2013, J. P. F. Zorzanelli & R. F. Zorzanelli 660 ( VIES) ; 30.V.2013, A. P. Fontana, L. Kollmann & J. P. F. Zorzanelli 7666 ( MBML) ; 20.VII.2013, L. Bacci & J. P. F. Zorzanelli 66 ( UPCB) .

Figures

FIGURE 1. Miconia valentinensis.A) Branch, showing the longitudinal ridge on the young branches; B) Leaf base, abaxial view; C) Leaf, adaxial view; D) Branch with inflorescence; E) Immature fruits; F) Incomplete flower with only five stamens. (photos A, C, E–F from Bacci & Zorzanelli 66; B, D, F from Bacci & Zorzanelli 129).

FIGURE 2. Miconia valentinensis. A) Longitudinal section of a flower, showing the internal and external surfaces of the hypanthium, and ovary apex; B) Caducous calyx, with the petals still adhered to it, adaxial view (CL: Calyx Lobes, P: Petals); C) Caducous calyx, abaxial view; D) Leaf base, adaxial view; E) Leaf base, abaxial view; F) Anther in lateral view, showing the longitudinal dehiscence; G) Flower; H) Stigma and part of the style; I) Stamen, lateral view; J) Detail of the leaf, abaxial surface; K) Young branch, showing the trichomes (Bacci & Zorzanelli 129, Holotype).