MR. C. T. DRUERY ON APOSPORY. 283 
and upon turning them over, the reason was obvious, since I 
immediately recognized the peculiarly woolly appearance of the 
sori indicative of apospory, the masses of incipient prothalli being 
in this case so large as to give in some places a suprasoriferous 
appearance to the frond. As Mr. Bolton very kindly provided 
me with material, I laid down several pinne with the excre- 
scences next the soil, and under close culture actual development 
immediately began, so that in a week or two each sorus had pro- 
duced a crowd of full-sized prothalli. Reporting progress to 
Dr. F. W. Stansfield, who had also received material, he 
wrote that in his case apical apospory was also appearing, 
2. €. prothalli were being developed from the apices independently 
of the sori. Examining my material, I found several apparent 
eases of this, which, however, on closer investigation, I found to 
be produced from small aborted sori situated so near the terminal 
point that the resulting prothalli seemed to spring therefrom. 
I therefore asked Dr. Stansfield to re-examine his material, with 
the result that in the majority of cases he found the appearance 
had been deceptive, but in some the apices themselves were 
certainly dilating. A little later I found an unmistakable instance 
of an apical prothallus, as can be seen by the culture I exhibit. 
Otherwise this case is identical with that of Athyrium Filiz- 
femina, var. clarissima, Jones, except that the growths are much 
more redundant. I have named the fern therefore Athyrium 
Filix-femina, var. clarissima, Bolton. 
It will be observed that in this case, as in all previous ones, 
the abnormality occurs on wild finds, and has not been induced by 
culture ; and considering the ease with which the prothalli are 
produced when the pinn are brought into contact with the soil, 
and the immense advantage which they must derive from being 
firmly attached to the frond from the beginning instead of, as in 
the detached spore, being at the mercy of a thousand and one 
disturbing factors, it is curious that the specimens found are 
solitary crowns instead of clumps. This advantage, however, in 
the struggle for existence is far more than counterbalanced by 
the absence of scattering spores, which limits the variety strictly 
to its birthplace. 
Finally, I exhibit young plants raised from the aposporous pro- 
thalli of Zastrea pseudo-mas, var. cristata, which I brought to the 
notice of this Society in November 1892. These are interesting 
as exemplifying exactly intermediate stages between me oophore 
