PROF. Е. О. BOWER ON APOSPORY AND ALLIED PHENOMENA. 321 
the presumable oophore originates as a lateral outgrowth from the presumable sporophore, 
there is little foundation for the view. We may well ask, is every lateral bud to be looked at 
in this light, or if not, where is the line to be drawn? It is found in the Mosses that, though 
in some cases the leafy buds do originate from the ends of protonemal filaments, they are, 
in the large majority of cases, lateral outgrowths ; it seems unnecessary on this ground to 
assume a third alternating generation in the life-cycle of the Mosses ; why, then, should 
so different an interpretation of the lateral budding be given in two groups of plants, 
which Dr. Vines admits (l. с. р. 361) to have strong affinities? But, again, the protonemal 
filaments formed in Pringsheim’s and Stahl’s cultures of the seta are not formed laterally, 
they usually appear longitudinally at the cut ends of the seta; thus even these cases of 
known apospory do not bear out Dr. Vines’s hypothesis. Since the Characee are of 
doubtful affinity, and since within the family itself there is no direct evidence for or 
against the view of Dr. Vines (for the further development of the presumable sporophore 
has never been observed), it would be rash to affirm a direct negative to the suggestion ; 
it must remain as a pure hypothesis until more cogent evidence is produced on one side 
or on the other. 
The phenomena of apospory may now be considered from the biological aspect: we 
have seen that the most prominent examples of it occur in isosporous plants; in these it 
is obvious that by means of spores the plant provides for the production of a large 
number of new individuals at a comparatively small cost to itself; while, owing to their 
small size, the spores are easily scattered, and the new individuals will thus be saved from 
entering into competition with the parent and with one another. Теге is no apparent 
reason for assuming that the formation of spores has any deeper significance than this 
in isosporous plants, where spore-formation is quite distinct from the sexual process ; 
further, the fact that the organism produced from the spore (the oophore) differs more or 
less from the sporophore, need not be regarded as of any more fundamental meaning than 
this, that in a certain stage of its cycle of life (the oophore) the plant adapts its vegetative 
structure to the production of sexual organs, and the temporary or permanent support of 
the embryo, there being по marked increase in number of individuals; while in another 
stage (the sporophore) it is adapted to carrying on vegetative functions ending in the 
formation of spores; these, if they germinate successfully, will ensure an increase in 
number of individuals. Now in those isosporous plants which show either induced or 
spontaneous apospory, the organism appears to exchange the chance of a great increase 
in number of individuals for a greater certainty of production of a few; instead of sowing 
the earth thickly with spores, only a few of which may succeed in passing the various 
dangers of germination and difficulties of self-support, the aposporous plants form by 
direct outgrowth a comparatively small number of prothalli, which have this great 
advantage over prothalli raised from spores, that for a considerable period they are 
supplied with nourishment from the parent plant *. It must be admitted that the rarity 
* It will be remembered that in certain cases the prothalloid growths assume a massive form, по doubt adapting 
themselves to the storage of nourishment thus derived. It seems then that in some cases these aposporous growths 
assume, as regards their nourishment, a condition not unlike that of the macrospores of the higher forms, since they 
carry with them a considerable store of reserve materials from the parent plant. 
