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relationship, it may be stated that spermogones sometimes 
occur — 
1. In the hypothecs! tissue of the apothecium itself, as in 
Celidium fusco-purpureum , Tul. [Mem., PI. 14., f. 12.] 
2. On the apothecium itself, as in Lichina pygmcea and 
confinis, and sometimes in Cladonia rangiferina. 
3. On the exciple of the apothecium, as in JJrceolaria scru- 
posa and Parmelia conspersa. 
b. Relative period of development, —-the spermogones nor- 
mally preceding the apothecia. Spermogones should there- 
fore be looked for in specimens hearing no apothecia or 
young apothecia ; when the apothecia are mature, we should 
expect to find the spermogones old, and perhaps degenerate. 
e. Relative abundance of spermatia and spores, — the former 
being infinitely more numerous than the latter. 
d . Relative size of spermatia and spores,-— the former being 
infinitely the smaller. 
e. Essential difference in structure between spermatia and 
spores, the former being solid, simple, or homogeneous, 
without septa ; the latter vesicular, frequently compound or 
septate, with heterogeneous contents. 
/. Essential difference in form, the spermatia being usually 
elongated and of extreme tenuity, the spores being generally 
oval or spherical. 
g. Greater constancy of size in spermatia than in spores, which 
are frequently very variable in this respect. Some sper- 
matia are much larger when attached to their sterigmata than 
when free— -as in some Parmelias ; but this is only an ap- 
parent anomaly, for it would appear that they normally split 
into two on being shed from their sterigmata. 
h. Absence of all germinative faculty, — so far as yet known. 
i. Similarity in structure between the capsule or envelope of 
the spermogone and the exciple of the apothecium, — the 
cellular tissue of which they are composed being generally 
the same. 
k. Constancy of occurrence of spermogones in ail lichens, and 
from every part of the world yet visited by man. 
9. Many lichens possess, in addition to apothecia and spermo- 
gones, minute organs, outwardly resembling spermogones, called 
