PROF. F. О. BOWER ON APOSPORY AND ALLIED PHENOMENA. 323 
remembered that in both the described cases the early stages of development of the 
sorus are according to the normal type; also, that if the abnormality be regarded as a 
reversion, the deductions which would follow from this would apply equally well to those 
врогорһогіс buds which arise іп the plumose Athyria in similar relation to the sorus. 
Again, the view that these abnormalities are reversions to an ancient type would run 
counter to those views of phytogeny which have been based upon a diligent comparison 
of known forms; in such a series of plants as @dogonium, Coleochete, Riccia, and 
Anthoceros there is ample indication of the formation of spores before the sporophore 
assumed its vegetative characters; in the lowest of this series the whole of the zygote 
goes to form the spore; it is only in the later terms of the series that a differentiation of 
vegetative tissue of the sporophore from the true spore-forming tissue becomes apparent. 
Thus, on phytogenetic grounds, it appears improbable that apospory is a true reversion. 
In the former of his papers on the Lycopodiacesx *, Treub draws attention to “the 
remarkable resemblance which exists between the young plant (asexual generation) and 
the prothallus (sexual generation)" in Lycopodium cernuum; he also remarks, “ the 
fact that the prothallus of Lycopodium cernuum is rather more differentiated than the 
prothalli known in other Vascular Cryptogams, makes this resemblance more striking ; " 
and continues, “I think I am able to state that in none of the Vascular Cryptogams is 
the analogy between the young asexual generation and the sexyal generation so great as 
in Lycopodium cernuum ; the fact is so interesting that I may be allowed to draw special 
attention to it now." This being so, if apospory be regarded as a reversion, it is among 
the Lycopods that we might well expect to find apospory occurring: hitherto, there is 
no recorded case of it in this family, a fact which further supports the view above 
expressed that the phenomenon of apospory is a sport, and not a reversion bearing pregnant 
interpretations with it T. 
It can scarcely be a matter of surprise that, as we leave the isosporous forms and 
ascend in the scale to the heterosporous plants, the phenomena of apospory should, if 
present at all, be less prominent. Where microspores are formed, it is clear that their 
arrest would entail loss of sexual function ; unless, indeed, single cells of the sporophore 
should act as pollen-tubes and effect fertilization: this has, as far as I am aware, never 
been observed; still it must be regarded as a possibility in the light of the facts of 
apospory in the isosporous forms. If, on the other hand, the macrospore be arrested, a 
substitutionary or aposporous development might take the form of the production of 
ova (either directly or with previous cell-division) from ordinary cells of the sporophore: 
in Strasburger's examples of Funkia and Nothoscordum we have at least a near approach 
to this, since the actual function of formation of embryos is assumed by superficial cells 
of the nucellus; here, however, there is apparently no fertilization of those cells, nor 
any previous divisions corresponding to those in the embryo sac: accordingly, they 
+ « Etudes sur les Гусоро@асе»,” par M. Treub, Ann. du Тата. Bot. de Buitenzorg, vol. iv. p. 135. 
t The general result of investigations on monstrosities in flowers of the higher plants may be compared with this 
(cf. Goebel, ** Vergl. Entwicklungsgesch. der Pflanzenorgane,” Schenck's Handbuch, vol. iii. p. 114, &е.). 
