Mertensia rufinervis Martius (1834: 111). Sticherus rufinervis (Mart.) Nakai (1950: 28). Type:— BRAZIL. Minas Gerais. Freireiss s.n. (holotype BR [BR0000006972165] photo!).
Mertensia spissa Fée (1869: 200). Type:— BRAZIL. Rio de Janeiro. Nova Friburgo. Macaé de Cima. Glaziou 2468 (lectotype designated here, P [P00633241] photo!, isolectotypes P [P00633243], [P00623242] photos!).
Gleichenia klotzschii Hook. (1844: 13). Dicranopteris klotzschii (Hook.) Ching (1940: 275). Dicranopteris klotzschii (Hook.) Nakai (1950:61). Type:— BRAZIL. Sellow s.n. (holotype K [K 000589350]!).
Plants terrestrial or epipetric. R hizomes 1.7–4.40 mm thick, with redish-brown rigid simple or branched hairs, glabrescent to tomentose. Fronds scrambling, 1–4–(6)-forked, ultimate branches 13.5–32.5 × 3–6.5 cm, ovate, apex pinnatifid, base asymmetric, inner side with reduced segments, external side with conform segments, ultimate segments linear 2.8–15 × 2–2.5 cm, margins revolute, abaxial surface green or pruinose, pubescent, rare glabrescent, with reddish, rare whitish, multicellular hairs, on the segments midrib, bacilliform glandular hairs on the midrib, secondary veins and laminar tissue. Buds covered by reddish multicellular hairs, pseudostipule present, accessory branches simple to pinnatisect. Veins 3–4-forked. Sori medial, with paraphyses.
Distribution and habitat: —Endemic of Brazil (Bahia, Minas Gerais, Rio de Janeiro, São Paulo). This species has a distribution mainly in the Cerrado domain, with few collections from the Atlantic Forest domain. It occurs mainly at forest edges at 800–1600 m.
Notes: — Dicranopteris rufinervis is recognized by the abaxial surface of the ultimate segments with multicellular reddish hairs, and bacilliform glandular hairs on the midrib, secondary veins, and laminar tissue. It has a preferential distribution in Cerrado areas, specially in Campos Rupestres formation.
In the original description of Mertensia spissa, Fée cited a collection of Glaziou as type. We found three correspondent specimens at P and chose the most complete one with original Fée label as lectotype.
Selected specimens examined: — Bahia: Lençois, 12°34’00.0”S, 41°23’00.0”W, 950 m, 03 April 1980, Noblick 1766 (HUEFS); Mucugê-Igatu, Chapada da Diamantina, 12º53’47”S, 41º18’42”W, 764 m, 29 January 2017, Salino & Moura 16256 (BHCB); Serra do Sincorá, Rio Cumbuca ca. 3 km S. of Mucugê, 850 m, 13º01’S, 41º21’W, 04 February 1974, Harley et al. 15956 (K). Minas Gerais: Catas altas, RPPN Santuário do Caraça, Caminho para Bocaina, 20º 12’ 48.2”S, 43º46’84.2”W, 1364 m 27 August 2008, Viveros 26 (BHCB); Conceição do Mato Dentro, Parque Natural Municipal do Ribeirão do Campo, 19º06’12.3”S, 43º34’28.3”W, 13 September 2002, Mota et al. 1780 (BHCB); Itamarandiba, Parque Estadual da Serra Negra, 18º00’55.5”S, 42º45’14.8”W, 1600 m 04 July 2006, Salino et al. 11278; Santana de Pirapama, margens do rio Paraúna, 18º38’17,5”S, 43º54’52.1”W, 882 m, 10 June 2007, Almeida et al. 1089 (BHCB); Santo Antônio do Itambé, Parque Estadual do Pico do Itambé, 18º24’05.9”S 43º18’57.3”W, 07 October 2006, Almeida et al. 596 (BHCB). Rio de Janeiro: Alto de Macaé, without date, Glaziou 4456 (RB); Rio de Janeiro, Pico da Tijuca, 14 June 1933, Brade 12555 (RB); Santa Maria Madalena, Serra da Forquilha, 4 February 1935, Brade 14354 (RB). São Paulo: Ubatuba, Parque Estadual da Serra do Mar, Núcleo de Picinguaba, Trilha do Pico do Cuscuzeiro, próximo ao marco da divisa entre Rio de Janeiro e São Paulo, 23°21’33.7”S, 44°50’53.0”W, 07 August 2001, Salino et al. 7317 (BHCB).