26 i 
Pteridophytes . vestigial? 
Scott 1 in discussing certain sporangia which are filled with 
parenchymatous tissue, express the opinion that they are ‘ more 
or less completely abortive sporangia.’ But as their position 
in the strobilus is uncertain, they have no direct bearing 
on the question under discussion in this paper. And here 
may be mentioned that curious fossil Phyllotheca deliquescens , 
Goepp. 2 : it seems uncertain what may be the true interpreta- 
tion of it, though Solms speaks of the genus as differing 
from true Equisetaceae in having its fertile spikes repeatedly 
interrupted by ordinary vegetative leaf- whorls. This, how- 
ever, cannot be closely compared with the ‘ Selago ’ condition 
of Lycopods. 
Lastly, there is the case of Cheirostrobus : Scott, in his 
monograph on this fossil 3 , worked from two specimens : one 
probably a peduncle, the other a more complete cone. The 
latter shows clearly a reduction in size of the basal sporangia 
and sporophylls. This is well seen in the section figured as 
Scott’s Photograph 15, and drawing 15, in which the lowest 
sporangium is barely one quarter the length of one of those 
at the middle of the cone: the whole outline of the cone 
is oval at the base, owing to the gradual diminution in length 
of the sporophylls and sporangiophores. On the peduncle 4 
the bases of the leaves or bracts are present, showing superior 
and inferior lobes : there is evidence, however, that the latter 
are smaller and simpler in structure than the corresponding 
lobes which are really fertile. As the foliage of the plant is 
unknown, it is impossible at present to base definite conclusions 
on these facts, beyond recognizing the reduction of the spor- 
angia, and of the ‘fertile segment,’ at the base of the cone, 
and on the peduncle. 
The general results to be drawn from these fragmentary 
facts from fossils are, that the strobili of fossils were not 
always definitely marked off from the vegetative region, and 
1 Phil. Trans., 1895, vol. clxxxv, B, p. 910 ; also Williamson, Phil. Trans., 1880, 
PI. XVI, Fig. 18. 
2 Solms-Laubach, Fossil Botany, Engl. Ed., p. 181, Fig. 17, B. 
3 Phil. Trans., vol. clxxxix, B (1897), p. 1. 4 Loc. cit., p. 17. 
