_ THALLOGENS. 20° LICHENALS. 
1. L. Parella Acharius—(PrrELte. Cran’s-Eyp Licnen.) Fig. 34. _ 
Crust dirty white, determinate, plaited and warty ; shields scattered, thi 
coneave, whole coloured. 
Habitat. Rocks in mountainous countries. 
Quality. Yields a purple dye, equal to that of Arehill. 
2. L. tartarea Acharius.—(Cuppear.) Fig. 37. 
Crust thick, granulated, and tartareous, greyish white ; shields scattere 
convex, at length flat, yellow brown inclining to flesh colour, with 
thick inflexed border, becoming wavy. 
Habitat. Rocks, &c.,in alpine countries. 
Quality. Yields a rich purple colour. 
Uses. Employed in dyeing yarn. The source of Litmus, used as a test for acids, wh 
it becomes red, and for alkalies, by which the blue colour is restored. ; 
Sticta. Acharius. 
Thallus \eafy, leathery, lobed, with numerous little cavities. Shields 
the under side, fixed by a central point, flat, surrounded by an elevat 
border, formed of the thallus. 
1. S. pulmonaria Acharius.—(Lunewort. Oax-tunes.) Fig. 42. 
- Thallus spreading, olive green, pale brown when dry, pitted and ne 
much lacerated, with broad rounded lobes ; shields marginal, 
brown, with a thick border. : 
_ Habitat, Trunks of trees in mountainous countries. 
Quality. Bitter. Furnishes a good brown dye. Nutritious. 
Uses. Pulmonary affections, hemorrhage ; a light diet ; as a substitute for hops. 
| Pentwea. Acharius. — | id 
_ Thallus leafy, horizontal, lobed, woolly beneath, bearing the shields o 
Fig. 42.—Stieta pulmonaria; natural size, 
