—84— 
As regards the charac- 
ter of its surface, the thallus 
may be smooth, with a bloom 
( pruinose ), powdery (; pulveru- 
lent ' ), mealy ( tartareous ), 
scufy, warty ( verrucose ), hairy 
(, tomentose ), cracked {rimose), 
covered with a network ( reti- 
culate ), divided into small, 
regular spaces ( areolate ), or 
Fig. 14. A, Cladonia pyxidat a; B, Cladonia crist atella. i n( lentations or depres 
Natural size. (Original.) sions (/ acunose ). 
In texture the thallus may be 
thin and papery {membrana- 
ceous), moderately firm ( cartila- 
ginous ), or tough like leather 
{coriaceous). 
Sometimes the soredia, in- 
stead of being mere granular 
heaps, become coral-like projec- 
tions, and are then called isidia. 
The different kinds of A Igae 
which serve as go nidi a are 
mostly either grass-green or 
bluish green. When bluish they 
are termed gonimia. Some of 
the commoner ’forms of gonidia 
are shown in Figs. 3 and 15. 
In a few cases gonidia occur in 
the hymenium, and are disseminated with the spores. 
Fig. 15. A, gonidia of Graphis scripta: B, goni- 
mia of Leptogium. Magnified about 250 
diameters. (Original.) 
The principal forms of apothecia are as follows: 
I. Hymenium exposed when mature gymnocarpous 
A. Hymenium solid at maturity. 
1. Rounded in outline, concave, flat, or convex. 
a. Disk margined, at least when young, by a thalline exciple— that is, one 
which is continuous with the thallus and the same in color. (Figs. 2 
and 4) SCUTELLIFORM 
b. Disk margined only by a proper exciple— that is, one which is a con- 
tinuation of the hypothecium. and which does not contain gonidia. 
*Saucer-shaped or shield-shaped, with the exciple distinct at the 
margin. (Fig. 16, A) patelliform 
tExciple coal-black lecideine 
^Exciple paler than the disk BIATORINE 
§Strongly convex or globular, the exciple at length covered or 
obscured by the disk. (Fig. 16. B) CEPHALOID 
c. Disk margined by both proper and thalline exciples. (Fig. 16, C) 
ZEORINE 
2. Elongated in outline, furrow-like, straight or curved, simple or branching- 
(Fig. 16, D) LIRELLIFORM 
B. Hymenium becoming a powdery mass of spores by disintegration of the thekes 
at maturity. (Fig. 16, E) CRATERIFORM 
II. Hymenium enveloped in a perithecium— that is, a proper exciple which is spherical or 
flask-shaped, and at maturity opens by a spore at the summit, through which the spores 
escape like spermatia from a spermagone. Within the perithecium is usually another 
layer (the amphithecium ) which gives rise directly to the hymenium. (Fig. 16, F) 
ANGIOCARPOUS 
