On Jan 26, 2005, lmelling from Ithaca, NY (Zone 5b) wrote:
Found throughout most of the moister regions of the world. There are 100 or more species in this genus, which are an ancient group of plants whose larger ancestors, along with horsetails (Equisetum), dominated as the world's vegetation around 250 million years ago. Considered more primative than ferns but more advanced than mosses, species range from tiny thread-stemmed plants to large epiphytes that from curtains of ferny foliage on limbs of tropical rainforest trees. All share a similar cord-like stems with overlapping, bright green or golden-green scale-like leaves.
Club mosses do not flower, but bear tiny spore capsules between the scales of delicate small cones (strobili).