A Revision of the North American Eurhynchia

Studies on aquatic Oxyrrhynchium (Brachytheciaceae), with an emphasis on O. pringlei n. comb

“…Crum and Anderson (1979) emphasized the blunted, obtuse, cuspidate or notched leaf apex found in many leaves. We found that while the apices of many leaves are blunt, a large proportion of the leaves also have pointed apices, like the ones figured in Grout (1933) and in Wyatt and Stoneburner (1980). It appears to us that a pointed apex is the basic condition, and in frequent cases where the leaf apex is blunt it has been deformed by the exaggerated development of the costa.…”

“…It exhibits a great deal of phenotypic variation, especially in Europe. The variability and synonymy of this species are discussed in Grout (1898) and Dixon (1924). Some populations are diminutive, straggling and complanate, with narrow leaves and acuminate leaf apices; other populations have broader, acute leaves and arching branches, forming large loose wefts.…”

“…This phenotype may be genetic in origin, but since it has arisen in unrelated moss lineages it is of little phylogenetic significance (Vanderpoorten et al 2003). Grout (1933) stated that the enormous costa of O. macroneuron is a morphological feature ''associated with lime in solution,'' and he compared the condition with that of Hygroamblystegium noterophilum (Amblystegiaceae).…”

“…Grout (1933) originally described the moss and tentatively included it in Hygroamblystegium. Crum (1969) moved the species to the Brachytheciaceae as a species of Eurhynchium (Platyhypnidium), but Crum and Anderson (1979) returned it to the Amblystegiaceae as the sole representative of a new genus Donrichardsia.…”