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Tropical Bryology 6: 65-69, 1992

Morphology of conjugata Lindb. (, Hepati- copsida)

Denise Pinheiro da Costa

Jardim Botânico do Rio de Janeiro, Rua Pacheco Leâo 915, CEP 22460, Rio de Janeiro, Brasil

Raul Dodsworth Machado

Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho

Abstract. Scanning electron microscopy and light microscopy were used to elucidate the morphology of Metzgeria conjutata Lindb. and confirm the presence of 2 rows of epidermal cells on the dorsal surface, (21-3) rows on the ventral surface, midrib with cells in (3-51-6) tiers; hirsute, short hairs, straight on the thallus-margin and on the ventral surface of midrib; marginal hairs paired, single or in groups of three; male branches globose or subglobose; female involucres obovate and hirsute at the margin, calyptra fleshy, pyriform to club-shaped, hirsute on the outer surface, hairs long and straight.

Introduction Metzgeria conjugata Lindb., Acta Soc. Sci. Fenn. 10: 495. 1875. The morphology of the family Metzgeriaceae has been described and illustrated by many authors Type-locality: Europe. in floristic papers to characterize the species belonging to this family. This paper deals with Gametophyte thallose, median-sized to robust, the morphology of Metzgeria conjugata Lindb.; pale green to green-yellowish, prostrate, 20-30 it was studied for the first time with a scanning mm long and 1-2 mm wide. Thallus plane to electron microscope (SEM) and the results were slightly convex, dichotomously branched, apex compared to those obtained with a light broad and obtuse, margin recurved. Unistratose microscope (LM), as a contribution to the lamina in transverse section with (10-) 12-20 (- of the family in Brazil; the Metzgeria- 22) hexagonal cells, 22-65 x 16-45 µm, midrib ceae is represented there only by the Metz- weakly convex on the ventral side, with 2 rows of geria, with 28 species and 7 varieties. Metzgeria epidermal cells on the dorsal surface (cells 22-70 conjugata was chosen because it is widespread, x 26-53 µm) and 2(-3) rows of cells on the ventral but in Brazil it is restricted to the southern and surface (cells 18-50 x 16-47 µm), medulla consi- southeastern regions. It belongs to the section sting of 17-20 cells, distinct from epidermal with the largest number of species. This study cells, 10-33 x 7-21 µm, in 3-5(-6) tiers, cells tested the usual technics of scanning electron walls thickened, with small trigones. microscopy in the Metzgeriaceae. 66

Thallus hirsute, hairs short, erect, at the thallus- are rectangular (fig. 1). The hairs are located at margin and on the ventral surface of midrib (40- the thallus-margin and on the ventral surface of 120 µm long), not branched; marginal hairs midrib (figs. 2-3). At the margin they are short usually geminate, sometimes single, occasional- and straight, geminate in some cells, single or in ly in clusters of 3. Gemmae at the margin. a cluster of three (fig. 4-5). In transverse section Monoicous. Male branches globose or subglobo- the thallus shows 2 rows of epidermal cells on the se, without hairs. Calyptra pyriform to club- dorsal surface and 2(-3) on the ventral surface; shaped, hirsute, hairs straight, 1.2 x 0.5 mm. the lamina is unistratose with (10-)12-20(-22) Capsule globose or subglobose, opening by 4 cells from the midrib to the thallus margin; valves, the outer layer of capsule wall with semi- medulla with 17-20 cells in 3-5(-6) tiers, with circular thickenings, the inner layer with nodu- wall thickenings (fig. 6-7). The gemmae are lose thickenings. Elaters 120-600 µm long, 5-9(- lamellar at the thallus margin (figs. 8-9). The 14) µm wide at midlength, with one spiral thic- male branches are globose or subglobose, wi- kening. Spores small, 23 x 25 µm, heteropolar, thout hairs, on the ventr