There is usually a single, unbranched vein.
Young plants are equally drought resistant.
The clubmoss life cycle differs from that of flowering plants. At maturity they will release microscopic, flagulated sperm cells. The sperm require water to swim to the egg cell which develops from cells of the megasporangia. Tissue surrounding the fertilized egg may carry on photosynthesis as well as provide stored food for the developing embryo. This entire structure may be shed or held in the leaf axils of the strobili while the embryo develops.