Ohio State University
General Plant Biology: Seedless Vascular Plants
Use this very concise summary except to become familiar with these examples of less complex plants. Some of the terminology is at a more advanced level.
CK-12 Foundation
Ck 12: Life Science: Vascular Seedless Plants
[Free Registration/Login may be required to access all resource tools.] Vascular seedless plants have vascular tissue but do not have seeds. Most of the large vascular seedless plants from ancient times are now extinct, but their smaller...
BiologyWise
Biology Wise: Seedless Vascular Plants and Their Characteristics
Explains what vascular plants are and the characteristics of seedless vascular plants. Gives detailed descriptions of whisk ferns, club mosses, horsetails, and ferns.