88 BOTANICAL GAZETTE [august 



immature sporangia of Lepidostrobus. In the immature sporangia 

 near the apex of the cone of L. Brownii (Unger) Schimper, Bower 

 (5) has observed that "the bands of sterile tissue extend to the 

 upper wall of the sporangium," but he has been "unable to estab- 

 lish beyond doubt the fact of the tissue connection between them 

 and the wall." A section through a cone of L. Oldhamius Wil- 

 liamson, "passing obliquely through the apex and displaying the 

 internal structure of the immature sporangia with great clearness," 

 has been figured and discussed by Mrs. Arber, as follows (see 

 fig- 42): 



The sterile plates in these young spore sacs are massive and well preserved 

 and give rise with great regularity to two smaller lateral processes one on 

 either side. The branches are not directly opposite to one another and the 

 main process is continued above its branches for a considerable distance. That 

 these outgrowths are of the nature of plates running in the direction of the 

 long axis of the sporangium and are not merely peglike structures is evidenced 

 by the fact that they present a general similarity of appearance in the seven 

 sporangia in which they are visible in the section presented in pi. 21, fig. i. 

 .... Another point which is established by comparison of the different 

 sporangia is that the sterile plate died out towards the distal end of the spore 



sac In older sporangia the sterile plates are relatively less important; 



the lateral branch plates seem to shrivel and disappear quite early. 



These very interesting facts seem susceptible of an interpreta- 

 tion favorable to the reduction theory, for if there is a phylogenetic 

 recapitulation in the development of this sporangium we can 

 scarcely escape the conclusion that at one time in the history of 

 the race the sporangium was divided more or less completely by a 

 stout septum into 2 loculi, ahd perhaps at an earlier period still 

 into 4 loculi if we may be permitted to interpret the branches of 

 the sterile plate of the more immature sporangia as the vestiges 

 of a transverse sporangia! septum in some ancestral form; for if 

 we observe the relatively great size and development of this sterile 

 plate with its branches in the least mature of this short series of 

 sporangia, it will at once seem highly probable that in sporangia 

 just a little less mature these branches would extend quite to the 

 lateral wall. For the first of these hypothetical ancestral forms 

 one could not wish for a representative more satisfactory than 

 Cantheliophorus, and for the second more remote tetrasporangic 



