Australia: The Land Where Time Began

A biography of the Australian continent 

Zosterophylls, Ancestral to Clubmosses

As they occur in the Rhynia Flora, Zosterophylls are known in great detail. They are ancestral to the Clubmosses that dominated early Palaeozoic floras. Leaves are small, scale-like appendages that cover the stems. The original leaves were small projections, presumably to increase the area of photosynthesis, later receiving a branch of the vascular system as they became larger and flattened. The sporangia are produced in the angles of the leaves. They declined after the Palaeozoic, presently being represented by 4 genera, Lycopodium, Selaginella, Phylloglossum, and Ioestes (Quillworts).

Sources & Further reading

1. Maey E. White, The Greening of Gondwana, the 400 Million Year story of Australian Plants, Reed, 1994