Notes on American Cladonias

Since our western hemisphere surpasses the eastern in number of species and varieties of Cladonias and in forms peculiar to the hemisphere, the genus should have a special interest for the American student of lichens. Nevertheless our American descriptions have been for the most part quite inadequate and many of our determinations consequently incorrect. Cladonias are the most variable of all our higher lichens and therefore the most difficult to describe definitely. The most variable characters are those which may be studied with the eye or with a good hand lens, yet the most careful observation, the best possible descriptions, and comparison with authentic specimens are all necessary to enable one to determine these plants with any degree of certainty. Size, form, color, lobing and branching and the presence or absence of cortex and soredia must be constantly kept in mind in the consideration of the horizontal thallus, and yet more in the study of the podetia