Meriania vasquezii Rob. Fern., R. Villanueva & Michelang., 2022

Rocío, Robin Fernandez-Hilario, Gonzáles, Pilar Rojas, Villanueva-Espinoza, Rosa, Lajo, Leticia, Wong Sato, Akira A., Paredes-Burneo, Diego, Pillaca-Huacre, Luis, Michelangeli, Fabián A. & Goldenberg, Renato, 2022, Nine new species and a new country record for Meriania (Melastomataceae) from Peru, Willdenowia 52 (1), pp. 39-74 : 66-70

9. Meriania vasquezii Rob. Fern., R. Villanueva & Michelang. , sp. nov. – Fig. 3 , 17 , 18 .

Holotype: Peru, Pasco, Prov. Oxapampa, Dist. Chontabamba, Ulcumano Lodge , 10°38'08"S, 75°25'39"W, 2244 m, 23 Feb 2021 (fl.), R. Vásquez, L. Valenzuela, E. Pinche & C. Rojas 45480 ( HOXA accession no. 077441 !; isotypes: MO!, MOL barcode 000009 !, UPCB accession no. 99426 !) .

Diagnosis — A species differing from other congeners by the combination of leaf blades with dense villose indumentum on the abaxial surfaces, inflorescences with flowers in regular dichasia at the ends of branchlets, subcalyptrate calyx with small dorsal projections (c. 3 mm long) and irregular dehiscence, campanulate, deep pink corollas, dimorphic stamens and antisepalous stamen connectives with laterally expanded descending dorsobasal appendages.

Morphological description — Shrub up to 2.5 m tall; young branches and petioles pubescent with stellate trichomes up to 0.25 mm long, sparsely to moderately on young branches, moderately to densely on petioles. Young branches quadrangular, 5–5.5 mm in diam., lacking wings, nodes without interpetiolar flaps. Leaves opposite, isophyllous. Petioles quadrangular, 2.2–5 cm long, without projections. Leaf blades coriaceous, 16.5–23.5 × 9.3–10.7 cm, broadly elliptic to ovate, apex acuminate, base rounded to obtuse, margin denticulate on distal half and entire to obscurely denticulate on proximal half, discolorous; venation acrodromous and suprabasal, with one or two pairs of secondaries (lateral nerves), diverging 3–7 mm from base of blade and an additional pair of faint submarginal veins running up to leaf apex, tertiary (transversal nerves) 40–44 on each side of primary, percurrent, 2–9 mm distant from each other, midvein, secondary and tertiary veins impressed, reticulation barely visible on adaxial surface, midvein and secondary veins salient, tertiary veins and reticulation prominent on abaxial surface; adaxial surface slightly bullate, dark when dry, glabrous or with sparse elongated trichomes with a substellate base, denser near base, up to 1.5 mm long; abaxial surface golden brown when dry, midvein, secondary veins, tertiary veins, reticulation and surface densely villose with elongated curly trichomes with a substellate base up to 2.5 mm long, evenly covering entire surface. Inflorescences terminal panicles, erect, 26.5–29.5 × 12.3–14 cm, submultiflorous; axis and peduncle densely tomentose with elongated trichomes with a substellate base up to 1 mm long, longer (up to 2.5 mm long) on nodes. Peduncle c. 7.5 cm long, quadrangular. Main axis 18.1–18.3 cm, quadrangular. Paraclades in 4 pairs, proximal 10.5– 14.7 cm long, distal 3.9–4 cm long; flowers in regular dichasia at ends of branchlets. Bracts foliaceous, persistent, 16.5–19.1 × 9.3–10.5 cm, petioles 2.2–3.4 cm long, shape and indumentum similar to principal leaves. Bracteoles caducous, c. 20 × 1 mm, linear, indumentum similar to ones on peduncle and axis. Flowers 5-merous erect, with campanulate corollas. Pedicels 9–12 mm long, golden brown, densely tomentose to villose covered with trichomes similar to ones on peduncle and axis. Hypanthium c. 11 × 7 mm, campanulate, sometimes slightly costate, ridges obscured by trichomes, up to 0.75 mm high, golden brown, outer surface densely tomentose to villose covered by trichomes similar to ones on pedicels, inner surface glabrous; torus glabrous. Calyx opening irregularly, golden brown, outer surface densely tomentose to villose covered by trichomes similar to ones on pedicels, inner surface glabrous; calyx lobes closely connate in bud, forming a subcalyptra, 7.5–8.5 mm long, each with a small claw-shaped dorsal projection, c. 3 mm long, at maturity splitting irregularly. Petals 25–31 × 23–26 mm, c. 4 mm wide at base, obovate and slightly asymmetric, apex rounded, margin entire, deep pink, glabrous. Stamens 10, dimorphic, all bent to one side of flower giving flower a zygomorphic appearance; antisepalous stamens with filaments 12–13.5 mm long, light purple, glabrous; connectives prolonged below thecae c. 1 mm (not including descending dorsobasal appendage), purple, glabrous, with two appendages, one descending dorsobasal, laterally expanded, 3–3.5 mm long, acute and slightly crowned, light purple, other appendage dorsal appendage a mere hump, c. 0.5 mm, broadly rounded, light purple, 1.5–2 mm from tip of descending dorsobasal appendage, anthers c. 11.5 mm long, lanceolate, purple, glabrous, straight or with its apical portion slightly reflexed, opening by one dorsally inclined pore, thecae surface corrugated; antipetalous stamens with filaments 12–13 mm long, light pink, glabrous; connectives prolonged below thecae 1–1.5 mm (not including descending dorsobasal appendage), purple, glabrous, with one descending dorsobasal appendage, 2.5–3 mm long, triangular, light purple, anthers c. 12 mm long, lanceolate, purple, glabrous, straight or with its apical portion slightly reflexed, opening by one dorsally inclined pore, thecae surface corrugated. Ovary 5-locular, superior, free, c. 6 × 4 mm, oblong and slightly 5-lobed, colour unknown, not exceeding hypanthium length, glabrous; style c. 20 mm long, purple, glabrous, slightly incurved at apex and opposite to anthers at anthesis; stigma punctiform and minutely papillate, c. 1 mm wide, whitish. Fruits and seeds not seen.

Phenology — Flowering occurs in February.

Distribution and ecology — Meriania vasquezii is endemic to high-elevation montane forests in the Oxapampa province in the Department of Pasco, on moderate slopes at 2244 m.

Conservation status — Meriania vasquezii is known from a single collection from Oxapampa province. Increased fieldwork in montane and premontane forests in this region has led to the discovery of several new species of Melastomataceae in recent years ( Cárdenas & al. 2014; Michelangeli & Goldenberg 2018, 2021). Therefore, the effective protection of the diverse habitats in Oxapampa province is a high priority. Following IUCN (2012, 2019) guidelines and based on an estimated area of occupancy of 4 km 2, we recommend the category Critically Endangered CR B 2ab(iii) for this species.

Etymology — It is an honour to dedicate this species to Rodolfo Vásquez, researcher at the Estación Biológica del Jardín Botánico de Missouri, who for over 30 years has made an incredible contribution to the knowledge of the flora of Peru. He wrote Flórula de las reservas biológicas de Iquitos, Perú ( Vásquez 1997) and led the publication of Flora del Río Cenepa, Amazonas Perú ( Vásquez & al. 2010a, 2010b).

Discussion — Meriania vasquezii is distinguished from other congeners by the combination of subcalyptrate calyces with small claw-shaped dorsal projections (c. 3 mm long) and irregular dehiscence, campanulate, deep pink corollas, dimorphic stamens and antisepalous stamen connectives with laterally expanded dorsobasal appendages. The species with calyptrate or subcalyptrate calyces and campanulate corollas usually have pink-orange to reddish orange petals (see additional comments under M. juanjil ). However, M. vasquezii is the exception within this group by its deep pink petals. Also, the only Peruvian species with a subcalyptrate calyx and campanulate corolla is M. juanjil .

In Peru, the species of Meriania with calyx lobes closely connate in bud can be separated into two artificial groups; species with calyptrate calyces [ M. acida , M. escalerensis (also described here) and M. tomentosa ] and species with subcalyptrate calyces ( M. juanjil and M. vasquezii ). Nevertheless, M. vasquezii is easily distinguished within the former group by its small claw-shaped dorsal projections on the calyx (vs absent in the other species) and dimorphic stamens (vs isomorphic). Meriania vasquezii most closely resembles M. juanjil . They share subcalyptrate calyces with dorsal projections and campanulate corollas, but both species can be distinguished by the leaf blade size (16.5– 23.5 × 9.3–10.7 cm in M. vasquezii vs 10.8–12.7 × 2.7–3 cm in M. juanjil ), arrangement of flowers at branchlet ends (regular dichasia vs 5–7-flowered umbels) and length and colour of the petals (25–31 mm long and light purple vs 11–13.5 mm long and pink-orange).

Figures

Fig. 3. Distribution map of Meriania bicentenaria and M. vasquezii.

Fig. 17. Meriania vasquezii – A: terminal fertile branch with inflorescence and detail of inflorescence branch; B: detail of abaxial leaf surface; C: detail of calyx apex; D: antisepalous stamen, lateral view, with detail of descending dorsobasal appendage; E: antipetalous stamen, lateral view, with detail of descending dorsobasal appendage; F: hypanthium and calyx after anthesis. – A–F from R. Vásquez & al. 45480.

Fig. 18. Meriania vasquezii – A: terminal fertile branch with inflorescence; B: detail of inflorescence; C: flower at anthesis, apical view; D: immature fruit. – A–D from R. Vásquez & al. 45480. – Photographs by Rodolfo Vásquez.