The spores are generally borne singly in the axils of specialized leaves (sporophylls) and these are often aggregated into cone-like strobili. The spores and sporangia are either all of one kind or of two different kinds. The thick-walled spores germinate into very small monoecious prothalli (gametophyte stage) that are mostly saprophytic. The sex cells which are produced on the prothalli develop into the independent sporophyte after fertilization.
| Key to the class LYCOPSIDA | |
1 | Sporangia solitary in the axils of sporophylls, usually aggregated into cone-like structures | 2 |
| Sporangia in pockets in the expanded bases of fleshy grass-like leaves | ISOETACEAE |
2 | Minute ligule absent; sporangia of only one kind | LYCOPODIACEAE |
| Minute ligule present at the base of each leaf and sporophyll; sporangia of 2 kinds, producing spores of different sizes Back to 1 | SELAGINELLACEAE |