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I. A gonidial layer is present whose special function is that of 
assimilation. This is, however, not conclusive, since all apothecia 
with a thalloid exciple contain gonidia (algae), and therefore aid 
in the process of assimilation. 
2. The extreme variability in the size and form of the pode- 
tium indicates that it belongs to the vegetative portion of the plant 
rather than the reproductive portion. Constancy in size and form 
is peculiar to the organs of reproduction. 
3. The association of a large primary thallus with a small po- 
detium and, vice versa,a small primary thallus (or none at all) with 
> well developed, much-branched podetia seems to indicate that the 
podetium is specially adapted to supplant the function of the pri- 
Mary thallus. 
4. Cladonias with highly developed podetia (C. furcata, C. rangi- 
Jerina, etc.) are quite generally sterile (devoid of apothecia) and 
with primary thallus rudimentary or wanting. It would be absurd 
to consider such plants as reproductive organs since their prime 
function is vegetative. 
Reinke admits that the podetia are phylogenetically derived 
from apothecia and thus in part agrees with Krabbe. The follow- 
ing are the main reasons for assuming that this is the case: 
I. Podetia are developed endogenously from the gonidial zone 
of the pr imary thallus, similar to the apothecia. 
2. Podetia have a radial structure similar to apothecia and 
‘pothecial stalks. This is in sharp contrast to the dorsiventral 
Structure of the primary thallus. 
3. The apothecia occur upon the podetia. An apparent €x- 
ception is met with in C. miniata in which the apothecia seem to 
be sessile upon the upper surface or margin of the primary thallus. 
In this case the podetium has become much reduced, while the 
Primary thallus has become much enlarged. 
The general conclusion at which Reinke arrives is that the fo- 
aetium is a true lichen-thallus phylogenetically derived from t he 
apothecium. 
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