Note 22 — PHYSIOGNOMY OF PLANTS.

p. 25.—“The Casuarinæ.”

Acacias which have phyllodias instead of leaves, some Myrtacesæ (Eucalyptus, Metrosideros, Melaleuca, and Leptospermum), and Casuarinas, give a uniform character to the vegetation of Australia and Tasmania (Van Diemen Island). Casuarinas with their leafless, thin, string-like, articulated branches, having the joints provided with membranous denticulated sheaths, have been compared by travellers, according to the particular species which fell under their observation, either to arborescent Equisetaceæ (Horsetails) or to our Scotch firs. (See Darwin, Journal of Researches, p. 449.) Near the coast of Peru the aspect of small thickets of Colletia and Ephedra also produced on my mind a singular impression of leaflessness. Casuarina quadrivalvis advances, according to Labillardière, to 48° S. lat. in Tasmania. The sad-looking Casuarina form is not unknown in India and on the east coast of Africa.