— 104 — 
in g indentations below. Ap. sub-scutellseform (appearing as if 
lecidiene), often clustered. On rocks in dry situations. 
Umbilicaria pustulata. 
c. Th. coriaceous, often very large, brown above, smooth and even ; below 
* intensely black with crowded short fibrils. Ap. (infrequent) much 
as in the last but with dk. ridged concentrically, On rocks in rather 
dry situations Umbilicaria Dillenii. 
14. a. Th. cartilaginous, lobes rounded, numerous and crowded, lacunose, 
pale grayish-green above, whitish or here and there blackening 
below; no fibrils at the margin. Ap. sub-pedicellate attached 
obliquely to the margins and summits of the lobes; th. ex. thin, 
entire or crenate. Sp. simple, ellipsoid. On trees and dead wood. 
Cetraria lacunosa. 
b. Much as in the last but with marginal fibrils and crenulate exciple. 
On trees and dead wood Cetraria ciliaris. 
c. Th. coriaceous, with rounded sinuses, strongly lacunose-reticulate, 
tawny or olivaceous: paler below, filbrillose in veins around naked 
spots. Ap. (infrequent) sessile at the margin of the lobes: th. ex. 
entire. Sp. cymbriform, 2-4-locular. On trees and rocks. (Form- 
erly esteemed as a pulmonary medicine from its resemblance to a 
lung) Sticta pulmonaria. 
d. Th. coriaceous, with rounded (sterile) lobes and narrower erect ones 
bearing at the end shield-shaped (often revolute) apothecia; thallus 
mostly veiny below and with long rhizoids. Ap. innate on the 
upper surface of the lobes: th. ex. torn-crenate when young. Sp. 
fusiform-acicular, 4-locular. On the earth or on rocks, mostly 
among mosses Peltigera .* 
e. Th. cartilaginous-membranaceous, with rounded lobes, not veiny 
below, and with short rhizoids. Ap. as in the last but reniform and 
borne on the under surface of the lobes. Sp. fusiform-ellipsoid, 4- 
locular, Mostly on rocks and trees Nephroma* 
15. a. Th. not gelatinous when moist 16 
b. Th. gelatinous when moist 20 
16. a. Th. pale green or straw-colored above, blackening below 17 
b. Th. grayish or whitish ash-colored above, blackening below 18 
c. Th. grayish or whitish ash-colored above, fawn-color or whitish 
below 19 
d. Th. olivaceous brown or bronze-colored above, blackening below and 
with black rhizoids toward the centre, membranaceous, closely 
appressed. Dk. chestnut; th. ex. crenulate. Sp. simple, ellipsoid, 
colorless. On trees and rocks Parmelia olivacea. 
e. Th. pale yellow to bright orange above, white below, rather loosely 
appressed. Dk. orange: th. ex. entire. Sp. polar-bilocular, ellip- 
soid, colorless. On trees and rocks near large bodies of water. 
Theloschistes parietinus. 
17. a. Th. cartilaginous-membranaceous, the lobes mostly rather narrow, 
