Life-History of Isoetes. 
257 
Postscript. 
Since the foregoing was written, an article 1 appeared in the 
December number of the Annals of Botany, in which some 
points considered in my paper were treated, although the 
major part of the article was concerned with a study of the 
development of the organs of the mature sporophyte. As 
I have only considered the development of the oophyte and 
the embryo, I will only call attention here to that part of 
Mr. Farmer’s paper that had to do with these. 
In regard to the sporophyte the only point to be noted is 
the development of the root. My observations agree with 
Mr. Farmer’s, except that I am inclined to attribute more 
than one initial cell to the plerome, and regard the first root 
decidedly as a primary organ of the embryo, and not as an 
adventitious one. 
Concerning the oophyte, there are a number of important 
particulars in which our results disagree. First : In /. echino - 
spora the nucleus of the ungerminated spore invariably 
occupies the basal part of the spore, and not the apex as 
described by Mr. Farmer for /. lacustris. 
Second : It was possible, by overstaining with gentian-violet 
and then withdrawing the surplus stain, to demonstrate the 
nuclei at all stages of germination. 
Third : The first stages of germination consist of a division 
of the nuclei alone. No signs of any formation of cracks in 
the protoplasm were observed ; division walls first appear 
after the number of nuclei reaches 30-50. 
Fourth : The number of archegonia is limited, and the 
mother-cells are very early differentiated. All the cells of 
the upper part of the prothallium are not potentially arche- 
gonium mother-cells. 
Fifth : There is not necessarily the sharp separation of the 
vegetative and reproductive portions of the prothallium that 
1 On Isoetes laaistris, L ; J. Bretland Farmer, Annals of Botany, vol. V. No. 
XVII. Dec. 1890. 
