Plagiochasma rupestre (G.Forst.) Steph.

  • Authority

    Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)

  • Family

    Aytoniaceae

  • Scientific Name

    Plagiochasma rupestre (G.Forst.) Steph.

  • Type

    Type (Bischler & Sergio, 1984). Madeira, Forster s.n. (neotype: Madeira. Funchal, Quinta do Bom Sucesso, Sérgio & Nobrega 3873, neotype, LISU; isoneotypes, BM, G, MADJ, PC).

  • Synonyms

    Aytonia rupestris G.Forst., Ruppinia rupestris L.f.

  • Description

    Species Description - Thallus 2.3-5 mm wide, usually bluish green, sometimes whitish or partly tinged with purple, with narrow purplish margins; apical adventitious branches rare. Epidermis covered with a hydrophobic deposit; epidermal cells 31-40 × 20-24 µm, with mediumsized, rarely small or large, usually not nodulose trigones. Epidermal pores (90-) 130-280 per mm2, not raised above epidermis, 5-6 µm diam., bounded by a single ring of 4-6 cells, often irregular in shape, radial walls ± thickened. Ventral scales purplish, sometimes borders lighter in color, of cells of the same size and shape, without papillae; appendages l-2(-3), triangular, apex acute, with 1-2 cells, or acuminate, with row of 2-5 long cells with thickened walls apically, hyaline or light red, rarely purplish, widest basally, 10-14 cells wide, not constricted but sometimes horizontally plicate, length/width ratio 1.7-5:1; margins not differentiated, without papillae. Male receptacle dorsal, rounded or reniform, with 8-50 antheridia. Scales of male and female receptacles hyaline or partly tinged with purple, acute, with 1-5 cells apically, margins without papillae. Archegoniophores dorsal, stalk usually 2-4 mm long, with 1-3 rows of thickened, yellow, red, or purplish epidermal cells. Involucres 1-3(-4), yellow or brownish, sometimes tinged with purple. Spores 70-87 µm diam., light or dark brown, with complete areoles on both faces, ridges tuberculate. Elaters with 2-3(-4) helical bands. Gametophytic chromosome number n = 9 or 18.

  • Discussion

    The species varies considerably, but in a similar manner in the Old World and New World populations.

  • Distribution

    Plagiochasma rupestre has a pantropical distribution, from 46°N to 40°S. The species is widespread in warm regions of the world and has been recorded from Europe, the Mediterranean area, Macronesia, SW Asia, India, tropical and S Africa, the Mascarenes, Australia, New Zealand, and Oceania. However, it has not been collected in E Asia and on the tropical Asiatic islands. In the New World, it is common in the S United States, Mexico, and warm-temperate S America.

    Australia Oceania| New Zealand India Asia|