PROF. F. О. BOWER ON APOSPORY AND ALLIED PHENOMENA. 303 
are to be looked for in those plants in which the sexual and sporal modes of reproduction 
are in the strongest antithesis to one another, that is, in those plants which show most 
typical alternation of generations. In these the two modes of reproduction are, as regards 
the individual, most distinctly separate, both in time and space; it is accordingly easier 
in these to recognize the characteristic features of the phenomenon than in such plants 
as the Phanerogams, in which the oophore generation is reduced, and the phenomena of 
sporal and sexual reproduction brought into closer relations one to another. 
The observations of Pringsheim and Stahl, above alluded to, have shown that a return 
from the sporophore to the oophore by a purely vegetative process, and without the inter- 
vention of spores (apospory), may be induced in certain Mosses by subjecting them to 
abnormal conditions. It is the object of the following pages to describe examples of 
similar phenomena in Ferns, in which group apospory has been till recently unknown. 
But whereas in the case of the Mosses the results were obtained by subjecting the plants 
to abnormal conditions, some at least of the examples of Ferns to be described show 
similar peculiarities even under normal circumstances. Тһе observations on the Ferns 
will now be described in detail, and the comparison with other similar phenomena, as well 
as the theoretical discussion of the facts, will be deferred to the close of the paper. 
Athyrium Filiz-femina, var. clarissima, Jones. 
This plant presents an abnormal mode of development of the sporangium, which has 
already been the subject of repeated notice *. The specimens upon which the following 
observations were founded were kindly supplied from plants in the possession of Mr. G. 
B. Wollaston and Mr. Druery. It is to the latter that the credit is due of having first 
fully recognized the peculiarity of the mode of propagation of this Fern, of having traced 
it through, and demonstrated, by cultures shown before the Linnean Society, that the 
plant produces prothalli without the intervention of spores. The actual plant from which 
the specimens now living were derived was bought by Colonel Jones from a local fern- 
collector in North Devon, by whom it had been found growing wild. It is, however, 
uncertain whether the peculiarities now shown were to be seen in the plant when first 
found. Col. Jones, who recognized it from the first as a distinct variety, failed in repeated 
attempts to raise it from spores, and, though he did not subject it to a microscopic exa- 
mination, he came at last to the conclusion that it produced abortive spores; this result 
was further confirmed by the experience of Mr. Wollaston, and it may be concluded that, 
whether the substitutionary growths subsequently found were present or not on the 
plant in the feral condition, it showed from the first an arrest of the spores. It is 
unfortunate that certain information is not to be had on this point, 80 that it might be 
possible to form an opinion as to the permanency of those peculiarities which the 
shows. 
ru sori of this variety of the Lady Fern be examined in August, it will be found 
that they are, to the naked eye, of almost normal appearance ; the indusium is normal, 
ж С.Т. Druery, Gard. Chron. 1883, p. 783; Journ. Linn. Soc., Bot. vol. xxi. pp. 354, 858; Е.О. Bower, Journ. 
Linn. Soc., Bot. vol. xxi. p. 360; Druery, Proc. Bristol Nat. Hist. Soc. vol. iv. ^s 
Z 
