Brachymenium sublinearis Canestraro & D.F.Peralta, 2020

Canestraro, Bianca Kalinowski & Peralta, Denilson Fernandes, 2020, New and endemic species of Brachymenium (Bryaceae, Bryophyta) in the Atlantic Rainforest of Brazil, Phytotaxa 446 (4), pp. 220-228 : 225-226

Brachymenium sublinearis Canestraro & D.F.Peralta , sp. nov.

Type:— BRAZIL. Paraná: Morretes, Parque Estadual Pico do Marumbi, Mata Atlântica, trilha do Olimpo, sobre tronco vivo, elev. 1100 m, 25°27’00’’S, 48°55’05’’W, 19 April 2015, Peralta, D.F. & Brito, O.S. 16799 (holotype SP460333!).

Figures 2 and 3C .

Diagnosis: — Plants medium-sized, dark green. Leaves appressed or contorted when dry, oblong-lanceolate, often asymmetrically curved above, margins bordered by 1–3 rows of narrow rectangular cells, serrate at distal half; basal cells quadrate; costa short-excurrent. Flagelliform branches occasionally present. Operculum conic. Exostome teeth sub-linear, apexes usually entire, exostome basal membrane low, segments rudimentary.

Plants medium-sized, dark green, in dense tufts; stems 1.3–2.0 cm long, simple or branched, central strand present; rhizoids dense at base. Leaves appressed or contorted when dry, spreading when wet, 0.1–0.2 cm long, oblong-lanceolate, often asymmetrically curved above, apex acuminate, usually falcate, margins bordered by 1–3 rows of narrow rectangular cells, serrate at distal half, plane or reflexed almost throughout; upper cells hexagonal to rhomboidal, 54–76 × 15–20 µm, basal cells quadrate to sub-quadrate, 20–70 × 12–23 µm; stereids present; costa strong, short-excurrent; awn conspicuous. Perichaetial leaves not much differentiated, 0.1 cm long, triangular-lanceolate. Flagelliform branches occasionally present in upper leaf axils. Dioicous. Setae 1.0 cm long. Capsules 0.3 cm long, erect, cylindrical to ellipsoid. Operculum 0.1 cm long, conic. Exostome teeth sub-linear, yellowish below, hyaline above, apexes usually entire, densely papillose, closely spaced; endostome yellowish, densely papillose, basal membrane above the half of exostome teeth length, segments rudimentary, cilia absent. Spores spherical, lightly roughened, 12–15 µm.

Paratypes:— BRAZIL. Paraná: Morretes , 22 July 2014, leg. Peralta, D.F. 15887, 15897 (SP!) ; loc. cit., 23 July 2014, leg. Peralta, D.F. 16129 (SP!) ; loc. cit., 18 April 2015, leg. Peralta, D.F. 16651, 16658 (SP!) . Rio de Janeiro: Angra dos Reis, 21 March 1995, leg. Yano, O. 23676 (SP!) .

Distribution and ecology: —Endemic to Brazil, in the states of Paraná and Rio de Janeiro ( Fig. 3A–C ). Corticolous and epipetric, exclusive to the Atlantic Rainforest.

Etymology: —The specific epithet is an allusion to the sub-linear shape of the exostome teeth.

Notes: — Brachymenium sublinearis has leaves oblong-lanceolate with margins bordered by 1–3 rows of narrow cells, serrate and falcate above, short-excurrent costa, conspicuous awn, cylindrical to ellipsoid capsule, conic operculum and entire exostome teeth ( Fig. 2 ). With regard to gametophytes, the presence of flagelliform branches and serrate leaf margins is similar to B. klotzschii (Schwägrichen 1942: 310a) Paris (1894: 123) and B. regnellii ( Ochi 1980) . However B. klotzschii has lanceolate, elliptic to oblong leaves with its margins reflexed almost throughout and bordered above by one row of narrow cells, straight leaf apex and exostome teeth perforate along the median line. Brachymenium regnellii differs from B. sublinearis by the sub-percurrent to percurrent costa (sometimes short-excurrent) which tapers above, discrete awn, leaf margins plane with one row of narrow cells, straight leaf apex and exostome teeth perforate along the median line.

Brachymenium sublinearis is similar to Brachymenium magellanicum (Sull. 1850: 316) Paris (1894: 124) , a Southern South American species ( Ochi 1982). Both have leaves with reflexed and serrate margins and strong costa. However, B. magellanicum is autoicous and has leaves crowded at the apex of the stem and a hemispheric, short-apiculate operculum. The gametophyte, peristome, operculum and leaf morphology of B. speciosum (Hook. & Wilson 1848: 748) Steere (1948: 98) are similar to that of Brachymenium sublinearis . It differs from the latter by the costa tapering above, sub-percurrent to excurrent, leaf basal cells rectangular and larger gametophyte size. Brachymenium speciosum is a Neotropical species ( Allen 2002) and has been excluded from Brazil (Canestraro & Peralta in prep.).

The new species is also similar to B. debilinerve B. Allen (1998: 107) due to the dark-green gametophytes, weakly twisted leaves, oblong-lanceolate and asymmetric above. However, B. debilinerve is endemic to Central America and has leaves with sub-percurrent costa and unbordered margins ( Allen 2002). Brachymenium sublinearis is close to Bryum leptotorquescens Müll. Hal. ex Brotherus (1897: 246) , a Neotropical and African species ( Allen 2013). Both species have bordered margins that are serrate above and a short awn; however B. leptotorquescens has greater size, sub-percurrent to short-excurrent costa and rectangular basal cells.

According to Ochi (1980 subgeneric classification), Brachymenium sublinearis can be placed in the Peromniom (Schwägr.) Mitt. (1869: 276) section, since it is dioicous and medium sized and has bordered leaves, erect capsules, conic opercula, narrow exostome teeth with a hyaline, fragile apical portion and cilia absent.

Figures

FIGURE 2. Brachymenium sublineare:A. Habit, wet.B.Vegetative leaf apex. C. Vegetative leaf base. D.Vegetative leaves. E. Perichaetial leaf. F. Cross section of the leaf. G. Cross section of the stem. H. Exostome teeth and endostome membrane. I. Endostome membrane. J. Spores. K. Flagelliform branches, dry. (A-H, J, K from Peralta 16651 SP460187; I from Peralta 16799 SP460333).

FIGURE 3. Distribution of the new species of Brachymenium in Brazil. A. The Atlantic Rainforest of Brazil in gray and detailed area in black square. B. Brachymenium elimbatum. C. Brachymenium sublineare.