. The Bryologist. Mosses; Liverworts; Lichens; Botany; Bryology. —23—. Fig. 3. Physcia aquila var. detonsa X 2. Physcia aquila (Ach.) Nyl., var. DETONSA TucKM. (Fig. 3.) This in- teresting lichen is found on rocks, occa- sionally on trees. In favorable locali- ties it grows in round patches, the outer ring lighter and smoother than the inner part, which gives it the specific name, '* detonsa," meaning shaved. The thal- lus at the margin is olive in color, but soon grows brown. The lobes are linear, fringed on the margins with cilia, to- ward the centre are thickly covered with isidioid lo
. The Bryologist. Mosses; Liverworts; Lichens; Botany; Bryology. —23—. Fig. 3. Physcia aquila var. detonsa X 2. Physcia aquila (Ach.) Nyl., var. DETONSA TucKM. (Fig. 3.) This in- teresting lichen is found on rocks, occa- sionally on trees. In favorable locali- ties it grows in round patches, the outer ring lighter and smoother than the inner part, which gives it the specific name, '* detonsa," meaning shaved. The thal- lus at the margin is olive in color, but soon grows brown. The lobes are linear, fringed on the margins with cilia, to- ward the centre are thickly covered with isidioid lobules. Beneath, the thallus is white with black fibrils, which form a thick black mat. The apothecia are rather small and are sessile, the disk is flat, dark brown, with a toothed, rough looking margin. The apothecia are numerous and are crowded in between the isidioid lobules, giving the surface a very rough appearance. Physcia OBscuRA (Ehrh.) Nyl. (Fig. 4). The thallus of this interesting and variable lichen is brownish, the lobes are linear, many-cleft, and flat, fringed with short dense black bristle-like fibrils. The under side is so thickly covered with short black bristles that it looks black, and in Fig. 4. Physcia obscitra. some specimens it really is, in others it is light at the margin. The apothecia are a very dark brown, the disk flat, the margin thickly beset with spine-like fibrils. It is found on mossy rocks and on trees. Physcia setosa (Ach.) Nyl. This lichen belongs to the obscura group, and resembles it very closely. The thallus is larger, the lobes are not so finely cut, and the color is not so dark. The lobes are fringed with black fibrils as are those of P. obscura, but not so densely. The apothecia are larger and are not surrounded by the stiff black fibrils but have a crenu- late margin. With some lichenists this is not made a distinct species, but a variety of P. obscura. Physcia pulverulenta (Schreb.) Nyl. (Fig. 5). Thallus covered with a fine whit
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, booksubjectli
