ABSTRACT
A classification of life-history strategies in bryophytes, based on trade-offs between gametophyte longevity v reproductive effort and on spore size v spore number, is compared with schemes based on sexuality and gemma production in liverworts, and a statistical analysis of life-history characteristics among species in three large orders of mosses. There is reasonable agreement, although the results suggest that the strategies should be regarded as noda within a continuous array of reticulate variation rather than as discrete entities. Evidence is presented that decreasing gametophyte longevity in colonist, fugitive and shuttle species is accompanied by trends towards monoecy and increasing reproductive effort. Production of specialized asexual propagules is particularly characteristic of dioecious colonists among the mosses, but occurs more widely among liverworts. These relationships are discussed in terms of factors likely to lead to rarity among bryophyte species.
