Monographs Details: Plagiochasma argentinicum Bischl.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Family:Aytoniaceae
Description:Species Description - Thallus 3.7-8 mm wide, yellowish or olive green, with narrow, purplish margins; apical adventitious branches few. Epidermis finely granulose on surface, epidermal cells 28-35 × 24-28 µm, with mediumsized to large, sometimes nodulose trigones. Epidermal pores 9-20 per mm2, raised above epidermis, 12-21 µm diam., bounded by 2-3 concentric rings of 6-8 cells, radial walls thickened. Ventral scales purplish, margin of 2-3 rows of light red or hyaline, sinuose cells; appendages 2-4, narrowly triangular and acuminate, purplish or light red, with row of 1-2 cells apically, widest basally (5-7 cells), not constricted, length/width ratio 3.3-4.5:1; margins bordered by sinuose cells, sometimes with a few teeth, without papillae. Male receptacles dorsal or at base of apical adventitious branch, rounded or reniform, with 20-30 antheridia. Scales of male and female receptacles purplish, or hyaline, or hyaline and tinged with purple, acute or apiculate, with some papillae on margins. Archegoniophores dorsal, stalk 0.5-1.3 mm long, with thickened, dark-red epidermal cells. Involucres 1-3, light brown or purplish. Spores 106-118 µm diam., light or dark brown, regularly areolate on both faces, areoles and ridges tuberculate. Elaters with 3-5 helical bands. Gametophytic chromosome number unknown.

Discussion:Plagiochasma argentinicum is easily recognized by the finely granulose epidermis and by the ventral scales being bordered by sinuose cells and having 2-4 narrow appendages.
Distribution:Catamarca Argentina South America|