Schusterolejeunea inundata (Spruce) Grolle

Sierra, Adriel M. & Zartman, Charles E., 2023, A taxonomic review of the Amazonian rheophyte Schusterolejeunea Grolle (Lejeuneaceae: Cololejeuneinae), with two new combinations, Cryptogamie, Bryologie 20 (4), pp. 107-122 : 110-112

Schusterolejeunea inundata (Spruce) Grolle

( Fig. 3 )

Journal of Bryology 11: 105 ( Grolle 1980).

LECTOTYPE. — Brazil. Est. Amazonas, fl. Negro , supra cataractas, ad arbores riparias, leg. Spruce L319 (lecto-, designated in Grolle 1980, MANCH!; isolecto-, G).

SPECIMENS EXAMINED. — Brazil. Amazonas, Presidente Figueiredo, Rio Uatumã, 1°57’45.4”S, 59°27’40.6”W, corticicola umbrófila na margem do igapó, 21.II.1978, Ivo P. et al. 3431 (INPA!); Heliofita coletado em tronco de palmeira, na margem da beira do igapó, 21.II.1978, Ivo P. et al. 3432 (INPA!); Rio Uatumã a 4 km da Cachoeira, 1°57’45.4”S, 59°27’40.6”W, sobre galhos de árvore da beira do igapó, 20.II.1978, Lisboa P. 1096 (INPA!); Santa Isabel do Rio Negro, Rio Cauaburi, 0°15’S, 65°55’W, 3.VII.1979, Schuster 79-10-288 (INPA!, NY); São Gabriel da Cachoeira, Igarapé Ia Mirim, above the camp to Morro dos Seis Lagos, 0°17’06”N, 66°40’36”W, abundant on rock, twigs and leaves along the river, 1.IX.2011, Zartman C.E. 8751 (INPA!, SP!); Roraima, Caracaraí, Parque Nacional Serra da Mocidade, Rio branco, 1°23’03.7”N, 61°39’23.0”W, 4.III.2017, Zartman C.E. 9867 (INPA!, PMA!); Rondônia, Guajará-Mirim, Pacáas Novos, along the Rio Pacáas novos, between its confluence with the Rio Mamoré and the first rapids, 10°51’40.8”S, 65°16’21.5”W, Varzea forest, epiphyll, immersed in river by rising water, 8-13.III.1978, Reese W.D. 13291 (INPA!, NY); on twigs under water in the river, 8-13.III.1978, Reese W.D. 13288 (INPA!, NY); Pará, Serra do Cachimbo, Serra Maze and vicinity, 1208-1229 km north of Cuiabá along Cuiabá-Santarém highway (BR 163), c. 5°55’S, 55°40’W, 100-200 m a.s.l., on mature, tall, humid forest on steep slopes and valleys, with occasional igarapés and igneous rock exposures, 18-22.V.1983, Reese W.D. 16797 (INPA!, NY). See Appendix 1.

DISTRIBUTION. — Schusterolejeunea inundata is distributed in the Amazon Forests of Brazil, Colombia, Guyana, Peru, and Venezuela ( Grolle 1980; Gradstein et al. 2001; Dauphin et al. 2008; Gradstein 2021). In Brazil, it occurs in northern region ( Gradstein et al. 2001), in the states of Amazonas, Pará (Lisboa & Ilkiu-Borges 2001; Santos & Ilkiu-Borges 2022), Maranhão ( Peralta et al. 2011), Rondônia and Roraima.

HABITAT. — The species Schusterolejeunea inundata is restricted to seasonally inundated habitats in the Amazon and Cerrado biomes as a rheophyte. It forms extensive dark mats on rocks, tree branches, exposed roots, and leaves that are seasonally submerged by black water tributaries ( Gradstein & Costa 2003; Gradstein 2020). It was also collected at the edge of the crater lakes of ancient volcanic origin at the Morro dos Seis Lagos (Amazonas state) ( Appendix 1).

ILLUSTRATIONS. — Spruce 1884; Kachroo 1967 (figs 4; 5) as Cladocolea inundata (Spruce) Schust. ; Gradstein et al. 2001 (fig. 53J-L); Gradstein & Costa 2003 (fig. 65A-C); Thiers 1984 (fig. 21); Lisboa & Ilkiu-Borges 2001 (fig. 7).

DESCRIPTION

Habit

Plants small to medium in size, 1-2.5 mm wide, pale to dark green, creeping to loosely pendant, highly branched, with numerous gametangia, usually with fertile innovations. Branches Lejeunea - type.

Stems

Primary stems 120-135µm in diameter, in cross-section with seven cortical and three medullary cells, cortical cells 25-45 µm in diameter, medullary cells 25-30 µm in diameter; stems with thick-walled cells, epidermis slightly enlarged, without hyalodermis; ventral merophytes two cells wide.

Leaves

Obliquely spreading, elliptical, [phone] (1600) µm long, (160) 280-770 µm wide, 1.5-4 (5) times as long as wide, apices rounded, plane, margins entire, bases of the lobes very narrow, insertion line only 2-3 cells long. Cells pellucid, thinwalled, trigones rare, oil bodies finely granular, 2-4 per cell; ocelli absent. Basal laminal cells long rectangular to fusiform (16-50×9-20µ m), mid laminal cells short rectangular, quadrate, rarely long to short hexagonal (10-25 ×10-20 µm), marginal cells mostly quadrate to short rectangular (10-30 ×10-16µm).

Lobules

Small narrowly lingulate with a narrow base, plane, narrowly ligulate, 200-418 µm long, 73-116 µm wide, covering 1/8 of the leaf lobes length, keels straight, formed by 2-5 cells, apex rounded broadly expanded (beyond the keel), standing obliquely upward or erect, parallel to stem. Teeth reduced, formed by two cells with a marginal hyaline papillae terminal at the lobule apex.

Underleaves

Small narrower than the stems (14-27 cells), 2-3× longer than wide (150-280×55-90 µ m), narrowly bifid with erect lanceolate lobes composed of 3-10 cells long, sinus deeply V-shape, lobes at base composed of 2-4 cells wide. Rhizoids brown, up to 11-16 µm wide and thick walls 3 µm wide.

Autoicous

Gametoecia numerous along the gametophyte. Antheridia on short lateral branches, spikes with 2-6 (8) imbricate pairs of perigonial ovate and bilobed bracts, which are emarginated at their apices. Bracteoles arise as underleaves for each bract pair.

Gynoecia 2-4 in a monochasial row, each gynoecium with one pycnolejeuneoid or lejeuneoid innovation which is again fertile (except for the outermost one). Perianths obpyriform, inflated, with five distinct keels, two ventral and three dorsal keels, margins entire. Sporophytes with a 595 µm long and 90 µm thick articulated seta. Capsules globular. Capsule valves with a plurifenestrate pattern. Elaters 1-3 per valve, one attached to the apical cells and others to the margins near the apex of the valve, 165-195 µm long, and 8-14 µm wide with sinuous, incrassated walls, without real spiral bands. Spores green and variable in shape, spherical to rectangular (50-85× 25-35µ m), and surface verruculose.

COMMENTS

In the field, it can be recognized by its dark green color with a loose and straggling habit, hanging from twigs, or in the base of trees and rocks in black water seasonally flooded igapó forests. Under the dissecting scope, it can be distinguished by its regularly pinnate, and narrow leaves which are widely spaced on their branches. The combination of its short leaf insertion, elongate elliptical to oblong leaves with a flat lobule, small underleaves, and five-keeled perianths in dense clusters, distinguish it from other rheophytic liverworts in the region.

Figures

FIG. 3. — Schusterolejeunea inundata (Spruce) Grolle: A-D, gametophytes in ventral view, showing androecia and gynoecia branches; E, lobule; F, underleaf; G, mid leaf cells. Micrography from Zartman C.E. 8751. Scale bars: A-C, 400 μm; D, 200 μm; E, F, 150 μm; G, 100 μm.