MOST RECENT SUPRAGENERIC CLASSIFICATION

The latest arrangement of genera in suprageneric categories for the Pottiaceae at the world level, which may serve for purposes of comparison, is that of Walther (1983):

Trichostomoideae

Trichostomeae: Timmiella, Pseudotimmiella, Trichostomum, Rhamphidium, Hymenostyliella, Weissia (including Hymenostomum and Astomum), Chionoloma, Phasconica, Aschisma, Trachycarpidium, Kleioweisiopsis.

Tortelleae: Tortella, Pleurochaete, Oxystegus, Pseudosymblepharis, Stephanodictyon, Serpotortella, Barnesia, Streptocalyptra.

Barbuleae: Barbula (including Didymodon and Trichostomopsis), Bryoerythrophyllum, Streblotrichum, Semibarbula, Husnotiella, Pseudocrossidium, Erythrophyllopsis, Morinia [= Mironia], Gertrudiella, Sebillea, Prionidium, Bellibarbula, Geheebia, Hydrogonium, Leptobarbula, Tetrapterum.

Hyophileae: Hyophila, Gymnostomiella, Teniolophora, Uleobryum.

Eucladieae: Eucladium, Gyroweisia, Gymnostomum, Hymenostomum, Tridontium, Reimersia.

Pleuroweisieae: Anoectangium, Molendoa, Pleuroweisia.

Pottioideae

Pottieae: Tortula (including Syntrichia), Desmatodon, Stegonia, Neohyophila (= Plaubelia), Crumia, Globulinella, Uleopsis, Willia, Sarconeurum, Phascopsis, Aloina, Crossidium, Pterygoneurum, Aloinella, Ulea (= Uleopsis), Streptopogon, Calyptopogon, Tisserantiella, Pottia, Acaulon, Phascum, Byroceuthospora, Hyophilopsis.

Scopelophileae: Scopelophila, Weisiopsis.

Cinclidotoideae

Cinclidoteae: Dialytrichia, Cinclidotus, Pachyneuropsis.

Leptodontioideae

Leptodontieae: Leptodontium, Tuerckheimia, Triquetrella, Rhexophyllum, Luisierella, Leptodontiella, Streptotrichum.

Walther's compiliation is clearly a synthesis of the major elements of Brotherus' (1924–25), Chen's (1941) and Saito's (1975a) treatments, and several recent papers of various authors in addition to his own ideas (see also discussion of Cladograms 17–19 under Phylogenetic Analysis). In the main, it serves well as a summary of modern thought for comparison with the taxonomic concepts and nomenclature recognized in the present study. Although there is little basis for comparison since Walther's arrangement is not based on rigorous analysis of all characters, the present study supports certain of the groupings above (see Table of Contents for an overview) but proposes many new relationships.

Study with electron (TEM) and light microscopy of the spore wall ornamentation of several genera of European Pottiaceae led Rejment-Grochowska (1978) to divide the Pottiaceae into informal “sections” grouping the following taxa: Cinclidotus; Anoectangium; Eucladium, Gymnostomum, Gyroweisia, Hymenostylium, Hymenostomum, Weissia, Trichostomum, Tortella; Barbula, Bryoerythrophyllum; Pottia, Acaulon, Phascum, Pterygoneurum, Desmatodon; Tortula; Aloina. Saito and Hirohama's (1974a) similar study (but using a scanning rather than a transmission electron microscope) of 19 species of 14 genera of Japanese Pottiaceae (one collection examined for each species) found only one apparent difference at the suprageneric level: the Trichostomoideae differed from the other taxa studied by the presence of “multistalked verrucae” on most but not all of its species studied. They pointed out that major differences between spore ornamentation may exist within the same genus (e.g. between Trichostomum crispulum and T. platyphyllum), while spores of different genera may be quite alike.

A major new character (Zander 1980a, 1989) that greatly affects the classification of the taxa recognized here is the upper laminal color reaction to two percent potassium hydroxide solution. The genera are for the most part well and consistently characterized intragenerically by KOH laminal color reaction, and suprageneric classification (see below) is in part based on this character. The species of Tortula, when split into KOH yellow (Tortula s. str.) and KOH red (largely Syntrichia and Hennediella) sets, are more similar to each other than to groups outside the Pottioideae, and share such apparently advanced characters as the broad leaf shape, lack of a ventral stereid band even in well-developed plants, and rather large upper laminal cells.