228 Bower. — Imperfect Sporangia in certain 
phyte. The cases quoted are chiefly from among the Club- 
Mosses, in which the problem is more readily handled than 
in most other Pteridophyta. 
Phylloglossum. 
I have already drawn attention to the fact that the tran- 
sition from the protophylls of this plant to the sporophylls is 
usually abrupt 1 . Occasionally the last of the protophylls to 
be formed is smaller than the rest, and thus it approaches 
in size to the normal sporophyll. But Mettenius 2 states that 
sometimes the fertile shaft bears a sterile bract some small 
distance below the strobilus. In my own specimens, in one 
case, a sporophyll of larger size than usual, with a sporangium 
attached, was found isolated below the strobilus 3 : thus there 
are indications of a transition between the protophylls and 
the sporophylls. In the strobilus itself all the lower sporo- 
phylls bear sporangia ; Bertrand remarks, however 4 , that 
though this is the case for the three lowest whorls of the 
spike, the sporangia on the fourth whorl are not always fully 
developed, those of the fifth whorl are atrophied, while those 
of the sixth bear but vague traces of sporangia : such spor- 
angia may appear only as slight convexities of the surface, 
while still higher all traces may be absent. Mettenius also 
noted that the sporophylls at the apex of the strobilus may 
be sterile. 
I have seen such abortive sporangia in the apical region 
of the strobilus of Phylloglossum ; I doubt, however, any 
numerical constancy of those fully formed, for I have seen 
sections of a strobilus in which the leaves of the fourth whorl 
were without any trace of a sporangium. 
It is thus seen that while there is in Phylloglossum as yet 
no detailed evidence of abortion of sporangia at the base of 
the strobilus, or in connexion with the protophylls, still 
occasionally there are intermediate types between the proto- 
1 Studies, i, p. 506. 2 Bot. Zeit., 1867, P* 99- 
3 Loc. cit., Pi. xliii, Fig. 22. 
4 Archives Bot. du Nord, vol. ii, pp. 83, 127. 
