The role of spores in reproduction in mosses

The facility for vegetative reproduction and reproduction by spores was compared in four common mosses by observations on naturally occurring spores, sporclings and juvenile shoots combined with experimental field plantings. In Polytrichum alpestre no evidence of spore germination in the field was obtained, but shoots were formed by regeneration from shoot fragments. Spore germination leading to shoot development, and ultimately to sporophyte production, occurred freely in Funaria hygrometrica. Atrichum undulatum and Bryum argenteum gave intermediate results in that regeneration occurred freely from shoot fragments, and while many spores germinated the sporelings normally failed to develop. There was strong evidence that experimentally planted spores occasionally gave rise to shoot production in both the latter species, however, and shoots commonly developed on protonema planted in the field. The results are discussed in relation to the contrasting life-history strategies shown by the four species.