GAMETOPHYTE 433 
swimming sperms (Fig. 385). The chimney-shaped archegonia 
are near the notch of the prothallus, and the globular anther- 
idia are in the region of the rhizoids. In some Ferns the male 
and female sex organs are on different gametophytes. 
The sperms are active swimmers and reach the egg by swim- 
ming down the neck of the archegonium which, like the arche- 
gonia of Bryophytes, opens at the top when the egg is ready for 
fertilization. From the neck of the archegonium, a substance is 
also discharged, which chemically attracts the sperms. 
Fic. 387. — A diagram of the life cycle of a Fern. A, sporophyte bearing 
sori in which the sporangia occur. B, a gametophyte, a product of a spore 
and the generation bearing the gametes, the sperms of which are shown 
passing from the antheridia to the archegonia. (', gametophyte bearing a 
sporophyte, which soon becomes independent and like the one at A. 
The fertilized egg immediately grows into a sporophyte, which 
lives on the gametophyte only until it has roots and leaves 
sufficiently developed to support itself (Fig. 386). After the 
sporophyte reaches maturity, sori are developed and the life cycle 
is completed (Fig. 387). Among a group of gametophytes one 
usually finds sporophytes in various stages of development and 
greenhouse attendants sometimes collect and pot the young 
sporophytes growing in unfavorable places, so that they mature 
and thereby increase their stock of Ferns. Usually, however, 
