Morphology of Gametophytes and Young Sporophytes of Sphaeropteris lepifera

Spl t lepifera is one of the largest tree ferns in Taiwan.On average, it produces = 7 sporangia per sa sorus, ee 64 spores per sporangium.Spore germination, after 2 years of storage 4°C was over 95%.The pattern of spore germination was "'Cyathea-type', and the gametophytes keel mainly Drynaria-type development with occasional Adiantum--type development.Typical gametophytes were heart-shaped but had the potential to elongate and become elliptical.Multicellular hairs on the dorsal and ventral surfaces of the midrib cushion increased in size and changed shape with age.They were usually uniseriate when young, and became multiseriate with age.Gametophytes initiated antheridia about 1 month after apes wane sown, and did not become hermaphrodites until 7 weeks later.During ontogeny, the sequence was from the male to hermaphroditic.Antheridia formed on the wings of the ventral and dorsal surfaces of gametophytes.The wall of each antheridium was composed of 5 cells.Archegonia appeared on the cushion of the ventral surface of gametophytes.Some gametophytes initiated clone-formation through vegetative regeneration.When sufficient water was provided, young sporophytes began to appear 12 weeks after spores were sown.The first fronds were midribless.The uniseriate, multicellular hairs on young sporophytes were similar to those on gametophytes.Gametophyte morphology, including mature forms, spore germination, and types of early development, trichomes, and gametangia, have been used to characterize fern taxa (Stokey, 1918(Stokey, , 1930;; Atkinson and Stokey, 1964; Nayar and Kaur, 1971; Atkinson, 1973).These characteristics provide information relevant to fern phylogeny (e.g., Nayar and Kaur, 1971) and the ecology and ge ae biology of different species (Chiou and Farrar, 1997a, b; Chiou et , 1998; Masuyama, 1975a Masuyama, , b, 1979)).a the Cyatheaceae, spore germination is Cyathea-type and gametophyte development is Adiantum-type or nearly Drynaria-type (Nayar and Kaur, 1971).