Abstract: | An electron microscopic comparison was made of the “isomorphic” sporophytic and gametophytic plants of Padina vickersiae. Light microscopic studies of the 2 generations showed few differences. This observation was also supported by studies at the ultrastructural level. However, minor differences in the gametophytic plant have been noted: (1) a well-defined nucleolus in the nucleus of the non-meristematic cell; (2) a general lack of osmiophilic globules in the chloroplasts; and (3) a clumping of chloroplasts in the maturing oogonium. The first and second differences are considered in terms of growth activity. |