Monographs Details: Mannia hegewaldii Bischl.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Description:Latin Diagnosis - Frons 2.5-3.5 mm lata, ecostata, non areolata, marginibus crispatis, purpureis. Cellulae epidermidis parietibus tenuibus. Porae epidermidis 2-3 annulis concentricis circumdatae. Cavemae 3-stratosae. Cellulae oleiferae brunneae. Squamae ventrales purpureae marginibus hyalinis papillosis, appendiculis 2-3, 6-7 cellulis latis. Monoecius. Antheridia et archegonia in pulvinis, squamis minutis purpureis circumdatis. Sporophyta in receptaculis hemisphaericis stipitatis 4-lobatis. Incolucrum cupuliforme. Capsula parietibus tenuibus. Sporae 68-76 µm diam., brunneae, alveolatae. Elateres 2-3-spiri.

Species Description - Thallus 2.5-3.5 mm wide, light green, smooth, not areolate, with broad, purplish, crisped borders. Branching dichotomous and ventral. Epidermal cells thin-walled. Epidermal pores with 2-3 rings of 6-7 cells, radial walls thin. Air chambers in 3 layers. Basal tissue with brown oil cells. Ventral scales purplish with hyaline margins, with oil cells and marginal papillae, with 1-2 acuminate, small-lanceolate appendages, 6-7 cells wide. Monoecious. Antheridia and archegonia in terminal cushions, bounded by few, minute, purplish or light-red scales. Archegoniophore stalk sometimes very long (20-30 mm), naked except apically with a few, purplish scales; receptacle 17.5 mm diam., broad-hemispherical, slightly asymmetrical and roughened dorsally by projecting epidermal pores, shallowly 4-lobed. Involucres cup-shaped, hyaline, margin entire to crenulate. Capsules with yellow-brown, hardly thickened walls. Spores 68-76 µm diam., brown, with yellow wing, distal face with large, finely tuberculate areoles. Elaters with 2-3 helical bands. Gametophytic chromosome number unknown.

Discussion:Mannia hegewaldii is closely related to M. triandra and has been attributed by Grolle (in litt.) to the latter species. However, a number of differences between the 2 species can be noted. The thallus surface in M. triandra is areolate, the thallus margins are hyaline, and the appendages of the ventral scales are narrower (maximally 5 cells wide). Moreover, the spores have narrower and more numerous areoles, which are coarsely (not finely) tuberculate. Because only few specimens are available, little can be said about morphological variation in M. hegewaldii. Additional, preferably living material is needed for a better understanding of the variation in this new species.
Distribution:La Libertad Peru South America|