Ferns are dominant sporophyte generation Phylum Pterophyta moist, tropical habitats, some aquatic, some live in arctic and dry areas. New emerging are curled tightly and called fiddleheads. Sori are clusters of sporangia, where spores are produced by meiosis. Spores germinate and grow by mitosis into the gametophyte called a prothallus Prothallus gametophyte is small, heart-shaped, lacks vascular tissue Rhizoids anchor prothallus Prothallus has antheridia and archegonia on bottom surface. Water is needed to transport flagellated sperm to archegonium.
Egg is fertilized and sporophyte grows out of the prothallus.
Phylum Psilophyta lack true roots and stems, but have vascular stems Dichotomous branching means branches are same size, not a dominant trunk. Sporangia are on stems and produce spores Spores germinate underground to give haploid prothalli Prothalli symbiotic with mycorrhizal fungi. Most species extinct. Living ones are in warm climates. Once dominant plants, as tall as trees.