Meriania sessilifolia (Cogn.) Rob.Fern., R.Goldenb. & Michelang., 2023

Fernandez-Hilario, Robin, Goldenberg, Renato & Michelangeli, Fabián A., 2023, A synopsis of Meriania (Melastomataceae: Merianieae) in Peru, Phytotaxa 602 (1), pp. 1-101 : 67-70

25. Meriania sessilifolia (Cogn.) Rob.Fern., R.Goldenb. & Michelang. , comb. nov.

Basionym: Centronia sessilifolia Cogn. , in A.DC. & C.DC., Monogr. Phan. 7: 459 (1891).

Type:— PERU. Piura: Huancabamba, 02 Dec 1881 (ster.), Poortmann 223 (lectotype, designated here: P! [barcode P00228659 ]; isolectotypes: BR!-fragment [barcode 000005628971 ], F!-fragment [accession no. 935561 ], P! [barcode P00228660 ]). Remaining syntype:— PERU. Piura: Huancabamba, 19 Jan 1883 (fl.), Poortmann 484 ( P! [barcode P 00228661 ]) . ( Figures 55–56 ).

Comments:— Centronia was traditionally characterized by the presence of large flowers, calyptrate calyces with circumscissile dehiscence, and stamen connectives with dorsal appendages ( Wurdack 1973). However, the first and third character are notoriously absent in the type of the genus ( C. laurifolia D.Don ). For this reason and other inconsistent characters within Centronia many species have recently been transferred to Meriania ( Almeda 1993, Mendoza-Cifuentes & Fernández-Alonso 2012). Also, phylogenetic analyses of the tribe Merianieae have shown that C. laurifolia is placed within Graffenrieda ( Dellinger et al. 2018, Caetano et al. 2020, Michelangeli et al. 2022; see additional comments in the introduction). On the other hand, Centronia sessilifolia has large flowers, calyptrate calyces with irregular dehiscence and spreading, reddish-purple corollas. These characteristics are present in other Meriania species and, therefore, we transfer C. sessilifolia to Meriania here as previously suggested by Mendoza-Cifuentes & Fernández-Alonso (2012).

Available specimens of M. sessilifolia (Department of Piura) consist of the original material, three sterile sheets (Poortmann 223) with leaf blades 5.3–6.8 × 1.8–2.3 cm, and another one (Poortmann 484) with only one flower without stamens, and recent collections from Cajamarca. The specimens from the Department of Cajamarca have notably larger leaf blades 11.8–20.8 × 4.8–7.5 cm. However, all specimens share sessile leaves, leaf blades with auriculate bases and suprabasal venation ( Fig. 55B ), and calyptrate calyces ( Fig. 55D ). Although the Cajamarca population may correspond to an undescribed species, for the moment we consider it with reservations as M. sessilifolia .

The only other Peruvian species with sessile leaves is M. amischophylla , but it is easily differentiated from M. sessilifolia by its lobed calyces with claw-shaped dorsal projections (vs. calyptrate calyces with callose dorsal projections, Fig. 56B ). Meriania maguirei Wurdack (endemic to Ecuador) is probably the species most closely related to M. sessilifolia by sharing calyptrate calyxes with irregular dehiscence and spreading, reddish purple corollas. However, M. maguirei can be easily differentiated by petiolate leaves (vs. sessile in M. sessilifolia ), leaf blades with acute bases (vs. auriculate), and glabrescent to glabrous hypanthia and calyces (vs. furfuraceous).

Nomenclatural notes:— Cogniaux (1891) cited as type “ Poortmann in hb. Drake ” in the protologue of Centronia sessilifolia . At Paris (P), three sheets, P00228659, P00228660 (both from Poortmann 223) and P00228661 (Poortmann 484) have labels indicating that they belonged to E. Drake´s herbarium, so these specimens must be considered as syntypes conforming with Art. 9.6 of the ICN ( Turland et al. 2018). Therefore, according to Art. 9.3 and 9.12 of the ICN ( Turland et al. 2018), we chose Poortmann 223 for lectotypification, because it allows to observe the sessile leaves with auriculate bases that characterize M. sessilifolia .

Distribution and phenology:— Meriania sessilifolia is endemic to northern Peru (Departments of Piura and Cajamarca) and grows in montane forests at 2250–2690 m ( Fig. 35 ). It has been collected in flower in January and October, and in fruit in October and November.

Specimens examined:— PERU. Cajamarca: Prov. Cutervo, Dist. Cutervo, CP San Cristobal del Nudillo, sector el Mirador y propiedad de Darwin Horna, 2690 m, 06°18’33.68”S, 78°51’40.71”W, 01–03 Oct 2012 (ster.), L. Dávila 2479 ( UNC!) ; Dist. San Andrés, Las Grutas, 2350 m, 13 Oct 1987 (fl., fr.), J. G. Sánchez 302 ( CPUN!, F!, US!) ; Dist. Santo Tomás, ceca al lugar Playa Grande, 2300 m, 14 Oct 1987 (fl.), I. Sánchez-Vega 4531 ( CPUN!, F!, US!) , PN Cutervo, rumbo hacia Playa Grande, 2250 m, 06°11’25.35”S, 78°44’40.74”W, 27 Nov 2020 (fr.), R. Fernandez-Hilario et al. 2097 ( CUZ!, HOXA!, KUELAP!, MOLF!, NY!, UPCB!) , same locality, 14 Nov 2022 (fl. bud, fr.), R. Fernandez-Hilario 2424 ( MOLF!) .

Figures

FIGURE 35. Distribution map of M. microflora, M. rigida, M. sessilifolia and M. zunacensis.

FIGURE 55. Meriania sessilifolia. A. Terminal fertile branch with infructescence. B. Leaf blade, abaxial view. C. Detail of the abaxial leaf surface. D. Inflorescence branch. E. Stamen, lateral view. F. Flower with petals and stamens removed. G. Fruit, apical view.A, C and G from R. Fernandez-Hilario et al. 2097; B from R. Fernandez-Hilario et al. 2424; D–F from J.G. Sánchez 302.

FIGURE 56. Meriania sessilifolia. A. Leaf blade, abaxial view. B. Flower buds. C–D. Terminal fertile branches with infructescences.A and C–D from R. Fernandez-Hilario et al. 2097; B from R. Fernandez-Hilario et al. 2424. Photos by Robin Fernandez-Hilario.