PROTHALLUS 27 
been thus dormant for a considerable time have been seen to revive 
when soaked out, and to continue their growth. They share in some 
measure that faculty which is so important to many Bryophyta, of recovery 
after dormancy under drought. Comparing the prothallus with the Fern- 
Plant as regards the water-relation, it is plainly less adapted for life on 
exposed land-surfaces, and more immediately dependent on moisture. 
Fic. 11. 
x. An attenuated male prothallus of Nephrodium Filix-mas ; 2-5. stages of development 
of antheridia ; 6, 7. ruptured antheridia; 8. a spermatozoid. (After Kny.) 
The prothallus thus constituted is capable in some cases of vegetative 
propagation, by gemmae, and other forms of ‘“gametophytic budding,” 
but this does not occur in the Male Fern. 
Though the close dependence on moisture for functional activity is 
thus seen in the prothallus, it is much more obvious in the behaviour 
of the sexual organs which the prothallus bears. These in the Male Shield 
Fern! are commonly borne, male and female, on the same individual 
1It is hargly necessary to say that the ‘‘Male” Fern is u misnomer, surviving from 
the misconceptions of earlier times. The Fern-Plant is neutral, being’neither male nor 
female, while it is on the prothallus that the sexual organs are borne. 
