nw North America in arctic and subarctic areas.
Genus 1, species 1.
Unlike the case with the similar Andreaeaceae, in Andreaeobryaceae the elevating stalk supporting the capsule is derived from sporophytic (diploid) rather than gametophytic (haploid) tissue. The foot of the seta is embedded in the vaginula at the stem apex, as generally occurs in mosses of the Bryales. Sporogenous tissue and the columella are derived from the endothecium, uniting the family with that of the Andreaeaceae in this respect, and not with the Sphagnaceae, where the spore sac derives from the amphithecium. The capsule is also unlike that of the Andreaeaceae, which is clearly elliptic, not angular-ovate. The family is also similar to Andreaea in the presence of thallose protonematal appendages. The axillary hairs at the base of the leaves have terminal cells that are beaked, as in the genus Takakia. The leaves are not particularly fragile, but fragmentation may prove a factor in asexual reproduction for the species. The following is a modification of B. M. Murray’s (1987) treatment.