Systèmes de croisement et fécondité chez le Sphagnum

Sexuality is most often preserved in Sphagnum while asexual reproduction remains responsible for the perennity and multiplication of the species. Sexual reproduction success was assessed for two diecious species and four monecious – polyecious species, using fertilization rates, reproduction rates, and success of the reproduction. The effects of different crossing processes on the preceding parameters were emphasized. Accordingly, gynoecium numbers, archegone numbers per gynoecium, and sporogonia occurrences were assessed in more than 3500 capitula. Variable distribution of gametangia within capitula in different species determines the success of sexual reproduction. An evolutionary interpretation of this variation in the distribution of gametangia is proposed. Key words: Sphagnum, crossing processes, polyecious, sexualization rates, reproduction success. [Journal translation]