Monographs Details: Exormotheca
Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press
Synonyms:Exormotheca pustulosa Mitt.
Description:Genus Description - Thallus 1-4 mm wide, not tinged with purple. Epidermal pores very strongly elevated above epidermis, with ring of 5-6(-8-10) hardly differentiated cells, radial walls thin. Air chambers with chlorophyllose filaments. Basal tissue with mucilage cavities. Ventral scales hyaline, with oil cells and marginal papillae, without or with 1-2 filiform, often forked appendages, not constricted basally. Monoecious or dioecious. Archegonia 1-4 per archegonial cavity. Archegoniophore stalk without assimilatory strip, with 1 rhizoid furrow and scales at top; receptacle usually 2-lobed, with pores bounded by a ring of ca. 7 cells. Calyptrae 2- to 3-layered after fertilization. Sporophytes 1-2 per involucre. Capsules opening by an irregular lid and 4-5 irregular valves to 1/2 of capsule length. Spore/elater ratio almost 1:1. Spores 5001500 per capsule, 50-150 µm diam., distal face with plates or flat protuberances, proximal face granulose-tuberculate, trilete scar distinct. Elaters with helical bands. Gametophytic chromosome number n = 8 or 16.
Discussion:A genus of ca. 7 drought-tolerant species of exposed rock outcrops and rocky soil, distributed in Mediterranean-type climates from 43°N to 33°S. The genus is everywhere rare. A single species occurs in the Neotropics.