Pharmaceutical botany - Lighthouse Survival Blog

68 PHARMACEUTICAL BOTANY
moving through the water are drawn by a chemotactic influence to
the archegonia of another prothallus, pass down the neck canals of
these and fuse with the ova, fertilizing them. The fertilized egg or
Fig. 37. Dryopteris filix-mas—Plant and section through sorus. {From Sayre.)
oospore divides and redivides and soon becomes differentiated into
stem bud, first leaf, root, and foot. The foot obtains nourishment
from the prothallus until the root grows into the soil, when it atrophies
and the sporophyte becomes independent. Unequal growth and di\-i-