Note 578 — BOOK XII. THE NATURAL HISTORY OF TREES.

It is clear that, under this name, certain lichens of a hairy or filamentary nature are meant. They adhere, Dioscorides tells us, to the cedar, the white poplar, and the oak. The white ones belong, probably, to the Usnea florida of Linnæus, the red ones to the Usnea barbata, and the black ones to the Alectoria jubata, an almost inodorous lichen.