EMBRYOLOGY 467 
early formation of the root, and late development of the axis and leaf: 
in the second, leaf and root only are developed, in the third roots only : 
the definitive sporophyte in both O. moluccanum and pendulum is 
“formed as an adventitious bud upon the root of the embryo sporophyte.” 
It would thus appear that the genus Ophzoglossum shows almost equal 
variety in its embryogeny to that seen in Lycopodium. It has been seen 
Fic. 260 dis. 
Ophioglossum vulgatum, L. 58= 
longitudinal section through a young 
seedling. 2 =first root with evident 
apical cell; /=the foot only slightly 
projecting ; e=the epibasal region of 
the embryo; f=rudiment of pro- 
thallus. X35.  61r=Tlarger, three- 
rooted seedling in longitudinal section ; 
f=prothallus; wy =first root; A= 
entering fungal filament; e2z=endo- 
phytic fungus. g@w=insertion of 2nd 
and 3rd roots; s=apex of rhizome: 
, bg, bg=leaves; c, c=canal; 4- 
A4,=sheath of first leaf; 22)-4/,=sheath 
of second leaf; A/3=sheath of third 
leaf. x35. (After Bruchmann.) 
in that genus how the different forms are referable to variation of a single 
type, and it seems probable that the same should be the case also for 
the embryos of Ophioglossum. In Lycopodium the variants arise through 
tuberous swellings and delay of root-formation: here the variants arise in 
relation to the precocity of the root, a feature related in all probability 
to mycorhizic nutrition. We have seen that the development of the axis 
is delayed in O. vulgatum, which may be held to be a less specialised 
type, though still with precocious root: in O. moluccanum, also, the root 
emerges early from the prothallus and projects downwards, but the 
