GAMETOPHYTES AND YOUNG SPOROPHYTES OF OPHIOGLOSSUM CROTALOPHOROIDES WALT.

The lens-shaped, dorsiventral gametophytes of Ophioglossum crotalophoroides are superficially different from the cylindrical gametophytes of other species of Ophioglossum. However, they have the same features as other Ophioglossum gametophytes (fundamentally axial organization, radially symmetrical apical meristem, radial distribution of gametangia) except that the cylindrical axis is reduced in length. Young sporophyte development is unique in the genus: all primary organs clearly arise from the embryo and develop simultaneously. The length of the life cycle of O. crotalophoroicles is considerably shorter than that of some other species in the Ophioglossaceae. A timetable for gametophyte and young sporophyte development is postulated. Spores germinate soon after they are released in the spring, and mature gametophytes develop by the next growing season. Fertilization occurs approximately one year after spore dispersal, and after two years, the photosynthetic first leaf of the young sporophyte emerges.