by Nathaniel Lord Britton & Addison Brown, An Illustrated Flora of the Northern United States… (1913)
“ On these are borne the sexual reproductive organs, the female known as archegones, the male as antherids. From the fertilization of the oösphere of the archegone by spermatozoids produced in the antherids, the asexual phase (sporophyte) of the plants is developed; this phase is represented by an ordinary fern, lycopod or horsetail. This subkingdom comprises about 6,000 living species, of which more than three-fourths are confined to tropical regions. The number of extinct species known probably exceeds those living. ”
