the Ophioglossaceae . 13 
spike is marginal or slightly away from the margin on the abaxial side. 
No examples of true ventral lobes have been adduced ; the sporocarp of 
Marsilia is stated by Van Tieghem ( 25 , p. 1405) to be such, but sections 
through the petiole at the point of attachment of the sporocarp (see Fig. 21) 
show that the origin is similar to that of the leaflets, namely, from one edge 
of a curved leaf-trace. Goebel ( 13 ) has described a species, M. polycarpa , 
in which several sporocarps arise in acropetal succession on one side of the 
petiole. The fertile lobes of Aneimia and of Schizaea are likewise lateral 
in origin, as a study of their vascular structure shows. Apparently the 
* ventral lobe ’ has a merely hypothetical existence outside of teratology. 
To bridge over the gulf which exists between the bryophytes and 
pteridophytes, as Campbell proposes to do in deriving Ophioglossum from 
Anthoceros , were indeed a consummation devoutly to be wished, but the 
gulf seems still to exist, for even in Ophioglossum simplex the aerial organ 
is borne laterally on a stem, the central cylinder of which is perforated by 
a gap at the point of exit of the traces supplying this organ. Even if it 
could be proved that the fertile segment is the main structure in the aerial 
organ and the sterile segment only an appendage, the sporangiophore is still 
a lateral organ, which arises from the stem just as does a leaf. Campbell’s 
latest contribution ( 9 ) on the subject seeks to show that the vascular supply 
of the fertile spike is not secondarily derived from the main bundles of the 
petiole, but that it can be traced to the base of the petiole. Hence the 
fertile spike is considered to be not a secondary but a terminal structure. 
According to this mode of reasoning, the basal pinnae in the leaf of 
Osmunda are terminal, for their ‘divergents’ (see 2 ) may be traced far down 
through the petiole. Similarly, in Botrychium virginianum, the divergents 
which pass off to the fertile spike may be seen for some distance below the 
point where the strands of the spike break off from the main supply, but the 
same is true of the divergents belonging to the divisions of the sterile 
segment. In this species the strands which supply the fertile spike do not 
break off until within a short distance below the point where the spike is visible 
externally, but appear very distinctly to be ‘ secondarily given off from the 
main bundles of the petiole ’. The evidence for Campbell’s view would be 
more conclusive if his figures left less in doubt as to the actual course of the 
vascular bundles which form the basis of his argument. All the cases where 
serial sections have been studied support the view that the strands which 
supply the fertile spike arise from near the edges of the leaf-trace, as do 
those supplying the pinnae of a fern leaf. 
The theory of Bower and others who consider the aerial part of the 
Ophioglossaceae to be a single sporophyll of a strobilus receives small 
support from the present investigation. The examination of the vascular 
supply of the fertile spike and the sterile pinnae of the leaf has shown the 
close similarity between Botrychium and an ordinary fern. The similarity 
