Morphological, ecological and molecular studies of the intergrading taxa Bryum neodamense and B-pseudotriquetrum (Bryopsida: Bryaceae)

Studies of Bryum neodamense at most of its localities in the British Isles revealed that plants with morphology intermediate with B. pseudotriquetrum var. pseudotriquetrum frequently accompany B. neodamense. A survey of herbarium specimens found that similar intermediates are widespread in continental Europe and also occur in Asia, Alaska and Greenland. Phylogenetic analyses of DNA sequences from three loci imply that B. neodamense and intermediate plants are nested within the rather variable B. pseudotriquetrum. It is therefore concluded that, despite its striking morphological characters, B. neodamense is an inconstant phenotype of B. pseudotriquetrum, which occurs very locally in highly calcareous habitats that are subject to periodic inundation.