Meriania rigida (Benth.) Triana, Trans.

Fernandez-Hilario, Robin, Goldenberg, Renato & Michelangeli, Fabián A., 2023, A synopsis of Meriania (Melastomataceae: Merianieae) in Peru, Phytotaxa 602 (1), pp. 1-101 : 57-60

21. Meriania rigida (Benth.) Triana, Trans. Linn. Soc. London 28(1): 66 (1871) [1872].

Chastenaea rigida (Benth.) Naudin , Ann. Sci. Nat., Bot., ser. 3, 18: 123 (1852). Basionym: Pachymeria rigida Benth. , Pl. Hartw. [Bentham] 130 (1844).

Type:— ECUADOR. Loja: in montibus prope Loja, 1842 (fl.), Hartweg 735 (lectotype, first step designated by Wurdack 1980, second step designated here: K! [barcode K000329439 ]; isolectotypes: BM! [barcode BM000939007 ], BR!-fragment [barcode 000005313341 ], F!-fragment [accession no. 1026704 ], G-probably destroyed [negative at F], K! [specimen from the right-hand side of sheet, barcode K000329440 ], LD! [barcode 1403377 ], S! [accession no. S05-3270 ]). Possible remaining syntype:— ECUADOR: Eastern Andes , 900 ft., (fl.), no collector 355 ( K! [barcode K 000329438 ]) . ( Figures 48–49 ).

Comments:— This species can be recognized by the combination of elliptic to oblong leaf blades, glabrous to sparsely puberulent abaxial leaf blades, with thick, callose dorsal projections ( Fig. 48E ), 5-merous flowers with isomorphic stamens, stamen connectives with triangular descending dorso-basal appendages, and dentiform to inconspicuous dorsal appendages ( Fig. 48I–J ). Due to the shape of the leaf blades and appendages of the stamen connectives, M. rigida can be confused with M. neillii . However, the latter can be differentiated by its 6-merous flowers and calyces without dorsal projections.

Paredes-Burneo et al. (2018) first recorded the presence of M. rigida in Peru based on material collected in Huancabamba (Department of Piura). But there are other populations in Peru that can also be attributed to M. rigida and there is variability among them all. The populations in Piura (Michelangeli et al. 2635 and Paredes et al. 526) have elliptic to broadly elliptic leaf blades 7–15.5 × 2.6–5.2 cm and slightly lobed calyces, while the population in Amazonas (Fernandez-Hilario et al. 1931, 1934 and Revilla et al. 3210) has moderately puberulent leaves ( Fig. 48F ), oblong leaf blades 5.2–9 × 4.7–6.5 cm and calyces with conspicuous lobes. On the other hand, the specimens Tarazona et al. P8-49 and Tarazona et al. P1-23 (both in fl. bud) collected in the Amazonas-San Martín border have small leaf blades (3.2–5 × 1.4–2.5 cm) with revolute bases and smaller flowers (hypanthium plus calyx 6.5–7.5 mm long). The Peruvian populations that best match with the typical population of M. rigida in Loja ( Ecuador) are in the Department of Cajamarca (Campos et al. 5892 and Díaz & Fernández 10217), these specimens have glabrous leaves, leaf blades 5.6–9.3 × 2.5–3.8 cm with revolute bases ( Fig. 48B–D ) and hypanthium plus calyx 10–11 mm long.

Despite the variability in the populations, all the specimens have the same inflorescence structure; it is a terminal panicle with short basal paraclades, main axis with three nodes and flowers on branchlet ends arranged in regular dichasia. Additionally, within each specimen examined, the stamen connectives have dorsal appendages that can be dentiform, truncate or inconspicuous. For the moment, we include with reservations all the Peruvian populations mentioned under the name M. rigida .

Nomenclatural notes:— According to Art. 9.10 of the ICN ( Turland et al. 2018), we have to consider that Wurdack (1980) made an inadvertent lectotypification (first-step) of M. rigida when he wrote “ Hartweg 735 (K, holotype) ” in his treatment of Melastomataceae for the Flora of Ecuador. However, there are two sheets of Hartweg 735 housed in K. Therefore, we designate the sheet K000329439 as the lectotype (second-step), conforming with Art. 9.17 ( Turland et al. 2018).

Distribution and phenology:— Meriania rigida occurs in Ecuador and northern Peru (Departments of Amazonas, Cajamarca, Piura and San Martín in montane forests at 1920–2800 m) ( Fig. 35 ). It has been collected in flower in February, July, October, and December, and in fruit in September.

Specimens examined:— PERU. Amazonas: Prov. Bagua, Dist. Copallín, camino a refugio Lechuza, Reserva Comunal Copallín, 1920 m, 05°39’25”S, 78°15’22”W, Jul 2022 (fl.), I. Revilla et al. 3210 ( MOLF!). Prov. Bongará, Dist. Yambrasbamba , colina cruzando la carretera al lado opuesta de la Estación Biológica Abra Patricia, 2360 m, 05°41’57.08”S, 77°48’33.83”W, 21 Feb 2020 (fl.), R. Fernandez-Hilario et al. 1934 ( HOXA!, KUELAP!, MOLF!, NY!, UPCB!), inmediaciones de la Estación Biológica Abra Patricia, trochas cercanas a la estación, 2280 m, 05°41’34.49”S, 77°48’34.94”W, 19–20 Feb 2020 (fl.), R. Fernandez-Hilario et al. 1931 ( CUZ!, HOXA!, KUELAP!, MOLF!, NY!, UPCB!), without locality, 05°36’52.69”S, 77°46’16.10”W, 29 Mar 2016 (fl. bud), M. Tarazona et al. P8-49 ( MOLF!). Cajamarca: Prov. San Ignacio, Dist. San José de Lourdes , base del cerro Picorana, 2050–2160 m, 04°59’25”S, 78°54’05”W, 04 Dec 1998 (fl.), C. Díaz & S. Fernández 10217 ( HUT!, NY!, USM!), Picorana , 2250–2300 m, 04°58’00”S, 78°53’01”W, 02 Dec 1998 (fl. bud), J. Campos et al. 5892 ( MOLF!, USM!). Piura: Prov. Huancabamba, Dist. El Carmen de la Frontera, Carretera Sapalache-Cerro Chingelas, 6.5 despues de Sapalache, catarata de Chorro Blanco, 2780 m, 05°08’09.7”S, 79°24’12.7”W, 03 Set 2016 (fr.), F. A. Michelangeli et al. 2635 ( NY!, USM!), Cerro Chinguela, catarata Chorro Blanco , 2803 m, 05°07’48.72”S, 79°24’10.08”W, 25 Oct 2015 (fl.), D. Paredes et al. 526 ( NY!, USM!), SOJO, Proyecto Minero Río Blanco, 2540 m, 04°53’58.88”S, 79°22’03.51”W, 20–21 Jun 2005 (ster.), A. Cano et al. 15729 ( USM!). San Martín: Prov. Rioja, Dist. Pardo Miguel, without locality, 05°38’58.36”S, 79°44’26.81”W, 03 Apr 2016 (fl. bud), M. Tarazona et al. P1-23 ( MOLF!) .

Figures

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

FIGURE 48. Meriania rigida. A. Terminal fertile branch with inflorescence. B. Leaf blade, abaxial view. C. Details of the abaxial surface. D. Detail of the revolute leaf base. E. Flower bud. F. Leaf blade, abaxial view. G. Details of the abaxial surface. H. Longitudinal section of the flower with petals, stamens and style removed. I, J. Stamens, lateral view, with details of the dorsal appendages.A–D from C. Díaz & S. Fernández 10217; E–J from R. Fernandez-Hilario et al. 1931.

FIGURE 49. Meriania rigida. A. Terminal fertile branch. B. Leaf blade, abaxial view. C. Detail of the inflorescence.D. Flower at anthesis, apical view.A, C and D from R. Fernandez-Hilario et al. 1931, B from F.A. Michelangeli et al. 2635. Photos by Robin Fernandez-Hilario (A, C and D) and Fabián A. Michelangeli (B).