Farmer . — On Isoetes lacustris, L. 61 
hinted at in so many other forms. The reduction of the 
oophyte has advanced along similar lines, wherever it has 
occurred, in the Vascular Cryptogams, and in the direction 
indicated above ; and it is from broader and more general 
comparative and morphological characters that the criteria of 
affinity must be derived. 
It is acknowledged by all modern writers that in reality 
Isoetes presents but little affinity with Selaginella. Goebel 
has even stated his belief that the ligule is perhaps the only 
important feature which they have in common, and I have 
attempted to show that the admitted community in this re- 
spect does not really advance the question at all. I myself 
entirely admit the force of Prof. Vines ’ 1 arguments in support 
of the affinity with the true Ferns, and I think that the general 
results contained in this paper do not in any way oppose such 
an alliance, although they show that it is not perhaps very 
close. This is however not a matter for surprise ; the hetero- 
sporous character of the genus clearly indicates a great advance 
on the homosporous condition of the Filicinae. 
Annals of Botany, vol. ii. 
