horsetail-lichen

(hérs’tal-li”ken), n. A popu- lar name for various species of A lector i a (particularly A. jubata), a genus of lichens, of the family Usneei, closely related to the genus Usnea. The thallus is slender, soon filiform, terete, and tufted or pendulous from the branches of trees, whence the plant is also called tree-hair and horsehair-lichen.