Filices.—Ferns.
Leafy plants with the fronds raised on a stipe (petiole) rising from a rhizome, circinate in vernation. The spore-cases are found on the under side of the frond. The life history of the fern is as follows:
When the minute spore from the sporangium on the frond drops to the ground, it germinates into a more or less heart-shaped body called a prothallus. The under surface of this body is provided with root-hairs and also female organs of generation, archegonia, and male organs, antheridia; the frond-stage is a direct outgrowth from the fertilized archeogonia.
