THE INDIVIDUALITY OF THE SPORANGIUM 111 
be supported on a basis of comparison among Angiosperms, though it is 
a less frequent change: examples are to be found in the coalescent ovules 
of certain Loranthaceae, or in the confluent pollen-sacs of certain Gut- 
tifeae, etc. Among Pteridophytes, on the other hand, the genera are so 
isolated as a rule that the comparative argument is difficult to apply: and 
Ay 
Fic. 61. 
Danaea elliptica, Smith. Drawings illustrating partial septations of the sporangium. 
A, tangential section through three sori, showing the loculi in ground plan: the septaare 
often thin, so that pairs of loculi are in close juxtaposition; the loculi marked (+) 
are large, and show one or more partial septa. 20. 1, C, D, £, show such loculi with 
partial septa in greater detail: in D and £ it is difficult to decide whether the cells 
marked (?) will develop as tapetum or as spore-mother-cells. 150. 
in each case of a synangium it may be a question whether the structure 
results from septation or from fusion. But without entering into these dis- 
cussions at present, it is plain that either way the individuality of the 
sporangium is lost in such cases, just as it is in the Angiospermic anthers, 
and this is particularly clear where, as often happens, partial septa are found. 
In summing up the considerations contained in the above pages, it may 
be asserted for sporangia at large, that the individuality of the sporangium 
