452 OPHIOGLOSSALES 
one another, that of the spike probably originating from one of the latest 
adaxial segments of the leaf-initial (Bruchmann, Zc, Fig. 55). Though this 
close proximity of origin of the fertile body to the apex of the sporophyll 
differs from what has been seen in Ofhioglossum vulgatumnt, still it has its 
parallel in the case of Zmesipteris, as already described: the details of 
segmentation are not the same, but the relation to the whole leaf is 
similar. Both parts in &. Lunaria retain their active initial cells till 
about the time of origin of the lateral pinnae: and it is specially to be 
Fic. 251. 
Ophioglossum vulgatum, L. Portions of sporangia showing the sporogenous tissue in 
two stages of disintegration. In A the tapetum (2), evidently derived from more than a 
single layer of cells, has formed a plasmodium with many nuclei, which is beginning to 
penetrate the sporogenous tissue, in which an occasional cell (s#) is seen disorganised. 
B shows a more advanced state, where the sporogenous cells (sf) appear in small clusters, 
or isolated, embedded in the tapetal plasmodium (2); w=sporangial wall. X x00. 
noted that the origin of these in Botrychium is by a process quite distinct 
from that of the fertile spike: the latter appears in a median position with 
a definite apical cell from the first: the pinnae arise in acropetal 
succession by marginal growth.! 
The disposition of the sporangia on the fertile spike of Botrychium is 
essentially similar to that in Ophioglossum, but they differ in being further 
apart, and not laterally coalescent, except in individual cases. The 
similarity is most readily recognised in the simplest examples (Figs. 252 4, 
B, C), in which the number of sporangia may be very small: these are 
disposed in lateral rows, obliquely facing the sterile frond: their position 
LLia, p. 218. 
