Pteridophyta, a diverse group of plants, have evolved more than Bryophyta in the following aspects:
1. Development of free-living sporophytic generation as the predominant phase.
2. Development of vascular tissue to conduct water and minerals from the soil.
3. Acquiring total terrestrial habitat.
4. In some species like Selaginella, development of two types of spores which later developed into seed habit in Gymnosperms and Angiosperms.
5. Reducing the gametophytic phase into a smaller, independent prothallus.
6. Some leaves bear the sporangia and are called as sporophylls. In ferns, the sporangia are grouped in a structure called sorus (plural sori). Such leaves, which bear the sori are called fertile leaves.
The sorus is surrounded by a kidney-shaped covering called the indusium, for protection. In some ferns, like Dryopteris, true indusium is present as it arises from the placental tissue, from which the sporangia arise. Conversely, in Pteris, false indusium is present as it is formed by leaf margin.