|Lycopodiella cernua with close-up of branch|
Clubmosses are thought to be structurally similar to the earliest vascular plants, with small, scale-like leaves, homosporous spores borne in sporangia at the bases of the leaves, branching stems (usually dichotomous), and generally simple form.
A powder known simply as lycopodium, consisting of dried spores of the common clubmoss, was used in Victorian theater to produce flame-effects. A blown cloud of spores burned rapidly and brightly, but with little heat. It was considered safe by the standards of the time.
The group is now split into two families:
- Lycopodiaceae: the typical clubmosses. Their spores are on a club-like structure. Their typical chromosome count is n=34.
- Huperziaceae: the firmosses. Their spore-bearing structures are in the axils of unmodified leaves. The family has a basal chromosome count of n=67.