Meriania zunacensis D. Fernández & Dellinger

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 : 70-72

10. Meriania zunacensis D. Fernández & Dellinger in Phytotaxa 458: 7. 2020.

– Holotype: Ecuador, Prov. Tungurahua, Cantón Baños, Parroquia Río Negro, Sector El Topo, Estación Cientifica Río Zuñac, Fundación EcoMinga , 01°22.593'S, 78°09.213'W, 1568 m, 26 May 2018 (fl., fr.), L. Jost, F. Recalde & S. Recalde 10600 ( QCNE barcode 243978 [1/2], QCNE barcode 243977 [2/2]; isotype: QCNE barcode 243976 ) .

– Fig. 9 , 19 .

Morphological description — Tree up to 20 m tall; young branches glabrous, petioles glabrous to moderately puberulent with simple trichomes, up to 0.13 mm long. Young branches quadrangular and ribbed, 4.5–5.5 mm in diam., nodes with interpetiolar flaps, 2.5–5 mm long. Leaves opposite, slightly anisophyllous. Petioles semiterete and adaxially ribbed, 2.5–5 cm long, with an adaxial projection (scutum) at insertion of petiole with leaf blade, up to 2 mm tall. Leaf blades subcoriaceous, 11.4–26 × 5.6–19.3 cm, ovate to broadly elliptic, apex acuminate, base broadly obtuse to rounded, margin entire, revolute at base, discolorous; venation acrodromous and basal, with two pairs or sometimes three pairs of secondaries (lateral nerves) and an additional pair of faint submarginal veins running up to leaf apex, tertiary (transversal nerves) 29–40 on each side of primary, percurrent, 1.5–14 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 visible or barely visible on abaxial surface; adaxial surface flat, dark green when dry, glabrous; abaxial surface green when dry, glabrous to moderately puberulent with simple trichomes, up to 0.13 mm long. Inflorescences terminal panicles, erect, 17.5–33 × 21–33 cm, multiflorous; axis and peduncle glabrous. Peduncle 5.5–14.5 cm long, quadrangular and slightly ribbed. Main axis 13–26 cm long, quadrangular and slightly ribbed. Paraclades in 4 pairs, proximal 14.5–23.5 cm long, distal 3.5 cm long; flowers in 4- or 5-flowered umbels at ends of branchlets. Bracts foliaceous, persistent, 15.3–20 × 10.3– 11 cm, petioles 3–4.5 cm long, shape and indumentum similar to principal leaves. Bracteoles not seen (probably early caducous). Flowers 5–merous, erect, with spreading corollas. Pedicels 6–15 mm long, green, glabrous. Hypanthium 11.5–12 × 18–18.5 mm, campanulate, green to light purple, outer and inner surface glabrous; torus glabrous. Calyx opening regularly, green to light purple, outer and inner surface glabrous; tube 6–8 mm long, entire; with 5 slightly callose dorsal projections, whitish and much lighter than rest of calyx and hypanthium when dry. Petals 40–50 × 33–37 mm, 8.5–9.5 mm wide at base, asymmetrically obovate, apex rounded, margin entire, reddish purple, glabrous. Stamens 10, isomorphic, all bent to one side of flower at anthesis giving flower a zygomorphic appearance; filaments 19–19.5 mm, light reddish purple, flat, glabrous; connectives not prolonged below thecae, purple in thecae, light purple in transition to descending dorsobasal appendage, glabrous, with one descending dorsobasal appendage, 6–7 mm long, triangular, cream; anthers 13–14.5 mm long, lanceolate, purple, glabrous, straight, opening by one dorsally inclined pore, thecae surface smooth surface. Ovary 5–locular, superior, free, 13–14.5 × 7–7.5 mm, ovate and 5-lobed, with apical ring of 5 tooth, c. 1 mm long, reddish purple, 6 mm exceeding hypanthium length, glabrous; style 15.5– 16 mm long, reddish purple, glabrous, incurved at apex and opposite to anthers at anthesis; stigma punctiform and minutely papillate, c. 1 mm wide, whitish. Fruits capsular (velatidia), with persistent hypanthium and calyx; mature ovary 13–14.5 × 8.5–11 mm, pyriform, slightly costate, 12–13 mm exceeding hypanthium length; fruiting pedicels 15–17 mm long. Seeds not seen.

Phenology — Flowering occurs in February, June and July and fruiting in February and July.

Distribution and ecology — Meriania zunacensis grows in high-elevation montane forests and elfin forests in Amazonas, Bagua and Bongará provinces in the Department of Amazonas, between 1500 and 2280 m. Populations of this species occur in pristine forests.

Discussion — During the preparation of this work we found specimens that did not correspond to any Peruvian species and we were in the process of describing them as a new taxon. However, the recent publication of Meriania zunacensis made us realize that these Peruvian specimens belonged to this newly described species, although some minor morphological differences do exist expanding some size ranges (see description). Meriania zunacensis was previously known only from Andean forests in Ecuador (Tungurahua province; Fernández-Fernández & al. 2020). We can now add three new localities in the Department of Amazonas in N Peru. Among Peruvian species of Meriania , nodes with interpetiolar flaps occur in M. callosa (see comments under this species for differences), M. megaphylla , M. sanguinea and M. tetragona . However, M. megaphylla has quadrangular winged internodes (vs quadrangular and ribbed in M. zunacensis ), leaf blades with cordate bases and bullate adaxial surfaces (vs broadly obtuse to rounded and flat surfaces) and calyces with blunt dorsal projections (vs without projections). Meriania zunacensis can also be distinguished by its petioles with adaxial projections (scutum) (vs abaxial projections; liguliform projections in M. sanguinea and tuberculate projections in M. tetragona ), leaf blades with entire margins and revolute at bases (vs serrulate margins and not revolute in M. sanguinea and M. tetragona ) and spreading, reddish purple corollas (vs campanulate, deep red corollas in M. sanguinea and M. tetragona ). A detailed comparison of M. zunacensis with other related species can be found in Fernández-Fernández & al. (2020).

Specimens examined — PERU: Amazonas, Prov. Amazonas, Dist. Vista Alegre , entre Vista Alegre y La Ventana a Naciento del Río Negro, 06°08'S, 77°18'W, 1500–1640 m, 2 Jul 1998 (fl., fr.), I. Sánchez & al. 9610 ( CPUN!, F!); Prov. Bagua, La Peca, 1850–1900 m, 14 Jun 1978 (fl. bud), A. Gentry & al. 23012 ( USM!, US!); Prov. Bongará, Dist. Yambrasbamba, inmediaciones de la Estación Biológica Abra Patricia, trochas cercanas a la estación, 05°41'43.40"S, 77°48'47.91"W, 2280 m, 19– 20 Feb 2020 (fl., fr.), R. Fernandez-Hilario & al. 1920 ( HOXA!, KUELAP!, MOL!, NY!, UPCB!); trocha Lechuza en la Estación Biológica Abra Patricia, 05°41'18.89"S, 77°48'23.68"W, 2123 m, 21 Feb 2020 (fl.), R. Fernandez-Hilario & al. 1938 ( HOXA!, MOL!, UPCB!).

Figures

Fig. 9. Distribution map of Meriania callosa, M. escalerensis and M. zunacensis.

Fig. 19. Meriania zunacensis – A: node with interpetiolar flap and adaxial projection on petiole apex; B: terminal fertile branch with inflorescence; C: flower at anthesis, apical view; D: immature fruits. – A–D from R. Fernandez-Hilario & al. 1920. – Photographs by Robin Fernandez.