Meriania bicentenaria Rob. Fern., R. Rojas & 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 : 40-44

1. Meriania bicentenaria Rob. Fern., R. Rojas & Michelang. , sp. nov. – Fig. 1–3 .

Holotype: Peru, Pasco, Prov. Oxapampa, Dist. Oxapampa, Abra Oxapampa-Villa Rica , 10°40'36"S, 75°18'55"W, 2300–2500 m, 6 Aug 2004 (fl., fr.), R. Vásquez, A. Monteagudo, L. Valenzuela, J. Perea & A. Peña 30366 ( HOXA accession no. 10648!; isotypes: NY barcode 03785787!, USM accession no. 215491!).

Diagnosis — A species differing from other congeners by the combination of roughened to dendritic trichomes evenly covering the abaxial surface of leaves, calyces with rounded lobes and without dorsal projections, campanulate, deep pink corollas, strongly dimorphic stamens, stamen connectives with acuminate to falcate, descending dorsobasal appendages and antipetalous stamens with inflated connectives.

Morphological description — Tree up to 35 m tall and 50 cm d.b.h.; young branches and petioles puberulent with roughened to dendritic trichomes up to 0.13 mm long, sparsely to moderately on young branches, moderately to densely on petioles. Young branches terete, 4–6 mm in diam., lacking wings, nodes without interpetiolar flaps. Leaves opposite, isophyllous, sometimes slightly anisophyllous. Petioles terete, 2.4–6 cm, with an adaxial projection (scutum) at insertion of petiole with leaf blade, up to 0.5 mm high, sometimes inconspicuous or obscured by trichomes. Leaf blades coriaceous, 10–18.9 × (2.9–) 5– 8.4 cm, elliptic to slightly lanceolate, sometimes broadly elliptic, apex acute, rarely obtuse, base obtuse to rounded, margin entire, discolorous; venation acrodromous and basal, with one pair of secondaries (lateral nerves) and an additional pair of faint submarginal veins running up to leaf apex, tertiary (transversal nerves) 33–48 on each side of primary, percurrent, 1–7 mm distant from each other, midvein, secondary and tertiary veins impressed, reticulation barely visible on adaxial surface, midvein and secondary veins salient, tertiary veins prominent and reticulation barely visible on abaxial surface; adaxial surface flat, brown, glabrous or sparsely puberulent with roughened to dendritic trichomes, denser near base, up to 0.13 mm long; abaxial surface light brown, midvein, secondary veins, tertiary veins, reticulation and surface densely pubescent with roughened to dendritic trichomes up to 0.13 mm long, evenly covering entire surface. Inflorescences terminal panicles, erect, 15.6–30 × 6.7–17 cm, multiflorous; axis and peduncle moderately puberulent with trichomes similar to ones on twigs and petioles. Peduncle 4.8–8.2 cm long, terete. Main axis 7.5–16.5 cm, terete. Paraclades in 5–7 pairs, proximal 5.9–11 cm long, distal 1.8–2.8 cm long; flowers in 4-flowered umbels at ends of branchlets. Bracts foliaceous, persistent, 10.6–16 × 4.3–6.5 cm, petioles 3.2–7.3 cm long, shape and indumentum similar to principal leaves. Bracteoles not seen (probably early caducous). Flowers (4 or)5-merous, with campanulate corollas. Pedicels 3.5–6 mm long, greenish to light purple, moderately puberulent with trichomes similar to ones on inflorescence axis. Hypanthium 3–4 × 5.5–7.5 mm, campanulate, greenish to light purple, outer surface sparsely to moderately puberulent with trichomes up to 0.13 mm long, similar to those on pedicels, inner surface glabrous to sparsely puberulent with trichomes similar to those on pedicels; torus glabrous. Calyx opening regularly, greenish to light purple, outer surface glabrous to sparsely puberulent with trichomes up to 0.13 mm long, similar to ones on pedicels, inner surface glabrous; tube 1–1.5 mm long; lobes 1–1.5 mm long, 3–5 mm wide at base, rounded, without dorsal projections. Petals 11.5–13.5 × 7–9 mm, 3.5–4 mm wide at base, oblong, apex asymmetric, margin entire, deep pink, apex sometimes slightly ciliate. Stamens (8–)10, strongly dimorphic, all bent to one side of flower at anthesis giving flower a zygomorphic appearance; antisepalous stamens with filaments 5–6 mm long, deep pink, flat, glabrous, connectives not prolonged below thecae, dark purple, glabrous, with two appendages, one descending dorsobasal, 3–4 mm long, acuminate, dark purple, other dorsal appendage a mere hump or inconspicuous, c. 0.25 mm long, broadly rounded, dark purple, 4 mm from tip of descending dorsobasal appendage, anthers 4–5 mm long, lanceolate, purple, glabrous, slightly curved, opening by one dorsally inclined pore, thecae with a smooth surface; antipetalous stamens with filaments 5–6 mm long, deep pink, flat, glabrous, connectives prolonged below thecae c. 0.25 mm long (not including descending dorsobasal appendage), abruptly inflated from 1–1.5 mm of tip of thecae, purple at apex, cream in first half of inflated portion and light purple in second half of inflated portion, glabrous, with one descending dorsobasal appendage, 3–4.5 mm long, falcate, dark purple, anthers 4.5–5 mm long, lanceolate, purple, glabrous, slightly curved, opening by one dorsally inclined pore, thecae surface smooth. Ovary (4 or)5-locular, superior, 3–3.5 × 3–4 mm, spheroid and slightly 5-costate, pink, not exceeding hypanthium length, glabrous; style 11.5–16 mm long, pink, glabrous, incurved at apex and opposite to anthers at anthesis; stigma punctiform and minutely papillate, c. 0.5 mm wide, deep pink. Fruits capsular (velatidia), with persistent hypanthium and calyx; mature ovary 5 × 5.5 mm, spheroid, slightly costate, 1.5 mm exceeding hypanthium length; fruiting pedicels 5–8 cm long. Seeds triangular-linear, c. 0.5 mm long, numerous.

Phenology — Flowering occurs from June to September and fruiting from March to November.

Distribution and ecology — Meriania bicentenaria is endemic to high-elevation montane forests in the Department of Pasco, between 2200 and 2550 m. Populations of this species usually occur in pristine forests and seldom in disturbed forests.

Conservation status — Meriania bicentenaria is known from five localities, growing in surroundings of the Yanachaga-Chemillén National Park. Following IUCN (2012, 2019) guidelines and based on an estimated extent of occurrence of 304 km 2, we recommend the category Endangered EN B 1ab(iii) for this species.

Etymology — The specific epithet commemorates the 200th anniversary of the Independence of Peru (1821– 2021).

Discussion — Meriania bicentenaria belongs to the M. macrophylla complex ( Wurdack 1978; Ulloa Ulloa & Homeier 2008), which is characterized by campanulate corollas, strongly dimorphic stamens and antipetalous stamens with inflated connectives. The M. macrophylla complex comprises six species distributed from S Mexico (state of Chiapas) to NW South America ( Colombia, Ecuador, Peru and Venezuela) ( Wurdack 1978; Almeda 1993; Ulloa Ulloa & Homeier 2008; Bussmann & Paniagua 2012; Almeda & al. 2020; Fernandez-Hilario & al. 2021).

Meriania bicentenaria , M. franciscana C. Ulloa & Homeier and M. ninakurorum (Bussmann & Paniagua) E. Cotton & Balslev are the only species of M. macrophylla complex occurring in Peru. Meriania bicentenaria occurs in central Peru (Department of Pasco), while the other two species occur in the N part of the country in the Departments of Cajamarca ( M. franciscana ) and San Martín ( M. ninakurorum ). These species are also the only ones within the complex that lack stamen connectives with descending bifid dorsobasal appendages. Meriania bicentenaria shares with M. ninakurorum the antipetalous stamen connectives without ascending appendages. Nevertheless, M. bicentenaria is distinguished from M. ninakurorum by the petioles with projections (scutum) (vs without projections in M. ninakurorum ) and leaf blades 10–18.9 × (2.9–) 5–8.4 cm (vs 23–32 × 9–15 cm). In addition, M. bicentenaria shares with M. franciscana the presence of an adaxial projection (scutum) at the insertion of the petiole with the leaf blade and roughened to dendritic trichomes on abaxial leaf surfaces. However, M. bicentenaria differs from M. franciscana by its leaf blades with entire flat margins (vs often slightly revolute at the base), abaxial leaf surface densely pubescent evenly covering the entire surface (vs sparsely to densely puberulent but without covering the entire surface), deep pink petals (vs reddish purple) and antipetalous stamen connectives without ascending appendages (vs with blunt ascending appendages).

Additional specimens examined (paratypes) — PERU: Pasco, Prov. Oxapampa, Dist. Palcazú, without locality, 10°32'S, 75°23'W, 2200 m, 4 Oct 1984 (fr.), D. Smith & al. 8685 ( F!); Dist. Oxapampa, camino a la Cordillera Yanachaga , 10°23'S, 75°27'W, 2400 m, 19 Jul 1984 (fr.), D. Smith & al. 7913 ( F!, US!, USM!) ; camino Oxapampa-Abra Villa Rica , 10°39'23"S, 75°20'27"W, 2270 m, 10 Aug 2004 (fl.), A . Monteagudo & al. 6960 ( HOXA!, NY!); camino Oxapampa-Villa Rica , km 37 en zona de amortiguamiento, 10°38'12"S, 75°24'45"W, 2462 m, 15 Mar 2006 (sterile), S . Vilca & al. 643 ( HOXA!, USM!); Cuenca del río San Alberto , 10°32'39.90"S, 75°22'13.63"W, 2286 m, 1 Oct 2019 (sterile), C . Llerena 23 ( MOL!); same locality and data (fr.), C . Llerena 32 ( MOL!); CDS , Sector San Alberto – Entrada al Parque Nacional Yanachaga Chemillén , 10°32'25"S, 75°22'14"W, 2290 m, 10 Jun 2021 (fl.), R . Villanueva-Espinoza 675 ( MOL!); Parque Nacional Yanachaga Chemillén , 10°32'S, 75°21'W, 2420 m, 26 Aug 2002 (fl., fr.), A . Monteagudo & al. 3807 ( AMAZ!, MOL!, NY!); Parque Nacional Yanachaga-Chemillén, cercanías del Refugio el Cedro , 10°32'51"S, 75°21'32"W, 2420 m, 26 Aug 2002 (fl., fr.), A . Monteagudo & al. 3808- A ( HOXA!); San Alberto , 10°32'43.54"S, 75°21'37.14"W, 2457 m, 24 Mar 2014 (sterile), R . Tupayachi & al. 13589 ( HSP!); San Alberto , 10°32'41.47"S, 75°20'29.34"W, 22457 m, 5 Mar 2014 (sterile), R . Tupayachi & al. 13601 ( HSP!); Sector San Alberto , 10°32'45"S, 75°21'24"W, 2468 m, 17 Aug 2006 (fr.), L . Cárdenas & al. 715 ( CUZ!, HOXA!, MOL!, USM!); PN Yanachaga-Chemillén, Sector San Alberto , zona de amortiguamiento, 10°19'S, 75°13'W, 2450 m, 16 Mar 2005 (fr.), R . Rojas & al. 3539 ( HOXA!, NY!); Dist. Huancabamba, PN Yanachaga Chemillén, Fundo Osobamba , 10°23'34.7"S, 75°28'28.1"W, 2243 m, 25 Jun 2016 (fl.), L . Valenzuela & al. 30395 ( USM!); Grapanazu, sector San Daniel , zona de amortiguamiento del PN Yanachaga-Chemillén , 10°26'36"S, 75°26'21"W, 2236 m, 8 Jul 2004 (fl.), J . Perea & al. 1445 ( HOXA!, NY!); same locality and data (fl.), J . Perea & al. 1449 ( HOXA!, NY!); same locality, 10 Jul 2004 (fl., fr.), J . Perea & al. 1467 ( HOXA!, NY!); Acuzazu , 10°30'24"S, 75°23'13"W, 2200–2300 m, 6 Jul 2004 (fl., fr.), R . Rojas & al. 3132 ( HOXA!, NY!); PN Yanachaga Chemillen, Sector Quebrada Yanachaga , 10°23'45"S, 75°28'55"W, 2300 m, 19 Aug 2004 (fl.), R . Vásquez & al. 30410 ( HOXA!, NY!, USM!); same locality and data (fl.), R . Vásquez & al. 30419 ( HOXA!); same locality, 10°23'38"S, 75°28'36"W, 2407 m, 20 Sep 2004 (fl., fr.), J . Perea & J . Mateo 1781 ( HOXA!, NY!); PN Yanachaga-Chemillen, parcela permanente 1.0 ha Oso Playa , 10°17'58"S, 75°36'35"W, 2200 m, 11 Nov 2006 (fr.), A . Monteagudo & al. 13406 ( NY!, USM!); Torre Bamba , 10°18'24"S, 75°35'06"W, 2550 m, 20 May 2004 (fr.), R . Rojas & al. 2403 ( HOXA!) .

Figures

Fig. 1. Meriania bicentenaria – A: terminal fertile branch with inflorescence; B: detail of leaf base, adaxial surface; C: detail of abaxial leaf surface; D: petal; E: antisepalous stamen, lateral view; F: antipetalous stamen, lateral view; G: flower with petals removed. – A–C from A. Monteagudo & al. 6960; D–G from R. Villanueva-Espinoza 675.

Fig. 2. Meriania bicentenaria – A: terminal fertile branch; B: leaf blade, abaxial view; C: flower at anthesis, lateral view; D: flower at anthesis, apical view. – From R. Villanueva-Espinoza 675. – Photographs by Rosa Villanueva-Espinoza.

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