1 1 2 Steil. — Apogamy in Nephr odium hirti'pes , Hk, 
in these, as in the two previously mentioned forms, originated as a vegetative 
outgrowth. 
So far as the nuclear history of apogamous ferns is concerned, that 
of the polydactyla varieties is of great interest. Nuclear migrations and 
fusions were observed by Farmer and Digby to occur between adjoining 
cells posterior to the apical region of the prothallium. From such a fusion 
or ‘ irregular fertilization ’ the apogamous embryo originated. In all the 
cases of induced apogamy, Farmer and Digby assume that similar migra- 
tions and fusions occur previous to the formation of the embryo. This con- 
clusion is based not alone on their investigations, but on the observations of 
Lang (1898), who found binucleate cells in the prothallia of some of the 
ferns in which he believed that he had induced apogamy (his Fig. 2 , 
PI. VIII). Heim (1896) also figured such cells in the prothallia of Doodya 
caudata (p. 338 , Fig. 7 ). Stephens and Sykes (1910) found binucleate cells 
in the prothallia of Pteris droogmantiana , which, however, resulted from 
a nuclear division not followed by cell division. Although Stephens and 
Sykes assumed the occurrence of apogamy in Pteris droogmantiana in 
their preliminary report, so far as I am aware no further contribution has 
yet appeared dealing with apogamy in this fern. 
Farmer and Digby (1907) made a detailed study of the chromosome 
number in the apogamous and parthenogenetic species. In Athyrium 
Filix-foemina var. clarissima , Bolton, eighty-four chromosomes were counted 
in both generations. Ninety chromosomes were found to be present 
throughout the life-history of A . Filix-foemina var. clarissima , Jones, 
and one hundred were counted in both generations of A. Filix-foemina var. 
unco-glomeratum , Stansfield. In each of these cases the number of chromo- 
somes present is, they conclude, presumably the sporophytic number. The 
nuclei of the prothallial cells of Scolopendrmm vulgare var. crispum Drum- 
mondae contain eighty chromosomes, but one hundred were found in the 
cells of the embryo. Between sixty and seventy-eight chromosomes — 
probably the gametophytic number — were observed in the nuclei of the 
aposporous Lastraea pseudo-mas var. cristata apospora. From sixty-four to 
sixty-six chromosomes were found in nuclei of the gametophyte of Lastrea 
pseudo-mas vars. polydactyla^ Wills and Dadds, and from one hundred and 
twenty-eight to one hundred and thirty-two in the sporophytic nuclei. The 
double number was, according to their description, established by the 
fusions of the nuclei' in the prothallial cells. 
Goebel (1905) found apogamy to occur in Trichomanes Kraussii 
and Peilaea nivea. 
Woronin (1907, 1908) discovered apogamy in Peilaea tenera y P . flavens, 
N othochlaena Eckloniana , and N. sinuata. Woronin investigated these cases 
and also the apogamy of the species reported by Goebel. Archegonia were 
never produced on the prothallia of any of these species, although normal 
