
No. 461.] AFFINITIES OF EQUISETUM. 277 
is marginal, and the meristem completely surrounds the upper 
part of the thallus, there being no proper apical growth as in 
Equisetum. 
The gametophyte of Equisetum can much more properly be 
compared with that of the lower ferns like Osmunda or Marattia, 

: ; = : f Bir ih 
Fic. 2. — A , archegonium of Botrychium virginianum ; B, Equisetum telmateia ; C, farat. 
tia Pr longitudinal division of the neck canal cell; D, Lycopodium clava- 
fum; E, Lycopod. 
jum phlegmaria ; 6, basal cell; o, egg cell; v, ventral canal cell; », #’, 
neck canal cells. (D,after Bruchmann ; Æ, after Treub. 
and in the former genus especially there are sometimes developed 
lobes not essentially different from those found in the gameto- 
phyte of Equisetum. | | 
As to the presence or absence of the basal cell of the arche- 


