468 



OPHIOGLOSSALES 



cotyledon, which is itself green and expanded, emerges upwards, while 

 the axis is still further delayed than in O. vitlgatum : it may be suggested 

 that the latter has been slipped out from the prothallus owing to the 

 early elongation of the base of the cotyledon, and so its original genetic 

 connection is not easily followed, and its appearance comes to be like 



a x 



' A 



| , J . . 



' 



' \ '-: 



' 



. 



. 







j 





Col 

 "*'''' ' ' : J v ''^' 



' 

 . 









a 



FIG. 261. 



Botrylniini nrginianiiiii, Sw. The 

 upper figures show two embryos ; the 

 arrows show the direction of the 

 archegonial neck, x = shoot ; ^> = root; 

 _/=foot; = initial cell of shoot; /> = 

 initial cell of root. X 250. The lower 

 figure shows an embryo more advanced ; 

 .t = stem ; r=root; c = cotyledon ; cal= 

 calyptra. x 50. (From Jeffrey.) 



that of an adventitious bud. Or possibly in this, as apparently in the type 

 of O. pendulum, the primary axis may be arrested completely (a step in 

 advance on the zw4"rtr////-type), and the adventitious shoots described as 

 originating on the root be actually such : in fact, early representatives of 

 those so often found on the roots of the genus. But from the facts, as 

 presented by Campbell, which are far from giving the complete develop- 

 mental story, there does not appear to be sufficient reason to regard the 



