Azolla filicu hides, Lam. i 71 
A section of the ripe spore, while still within the sporangium, 
shows its contents to be nearly- uniform. The granular proto- 
plasm is arranged somewhat reticulately, and in the living 
spore there is a good deal of oil, which is dissolved out in the 
process of imbedding. Besides this there are numerous albu- 
minoid bodies of varying sizes, that stain deeply with alum- 
cochineal. The nucleus (Fig. 40 n) is at the top of the 
spore-cavity, and is not at all conspicuous. It is somewhat 
elongated and quite uniform in structure, apparently having 
very little chromatin, and scarcely staining at all. No 
nucleolus can be seen. 
The first indication of germination is an increase in the size 
of the nucleus, which becomes nearly globular, and, at the 
same time, it shows more coarsely granular contents, and 
a small nucleolus becomes evident (Fig. 41). At this time the 
cytoplasm in the vicinity of the nucleus becomes free from 
large granules, and this is the first indication of the position 
of the mother-cell of the prothallium. 
While we have no observations on the first divisions in the 
prothallium of Azolla , there have been some partial observa- 
tions on that of the related Salvinia. Prantl 1 succeeded in 
demonstrating that the first division was by means of a distinct 
cell-wall, and that there was no formation of free cells such as 
Juranyi 2 describes. Prantl. however, failed to get the imme- 
diately following stages, although from a study of the older 
prothallia he was able to tell with considerable accuracy the 
succession in which the earlier walls were formed. 
The earliest stage obtained by me showed the very recent 
separation of the prothallium mother-cell (Fig. 42). This was 
a small lenticular cell, whose contents were more uniformly 
granular than that of the body of the spore. The division- 
wall was delicate, but easily seen. The nucleus stained deeply, 
much more so than that of the undivided spore, and had a much 
larger and more distinct nucleolus. The other nucleus was 
1 Zur Entwicklungsgeschichte des Prothalliums von Salvinia nalans, Bot. Zeit. 
1879, p. 425. 
2 Ueber die Entwickelung der Sporangien u. Sporen der Salvinia natans , p. 18, 
N 
