l8 9i-] Relationships of the Archegoniata. 329 



* 



ence upon the prothallium, as well as the great development 

 of the calyptra. all of which are evidences of the primitive 

 character of the group, and in all of which, so far as known, 

 it approaches the Eusporangiatae. An interesting point noted 

 was the fact that the primary root grows from a single tetra- 

 hedral apical cell, as in all of the Filicineae except the Marat- 

 tiaceae and Isoctcs, while the later roots, at least of the two 

 species studied, 0. Claytoniana and 0. cinnamomea, possess a 

 four-sided pyramidal apical cell. This seems to indicate that 

 the former is the primitive form which has been retained in 

 all except the Marattiaceae and the probably allied Isoetes. 

 Whether this state of things obtains in the embryo of the for- 

 mer of these is not known, but it is nofrimpossible; in the lat- . 

 ter a trace of this is sometimes seen in the very earliest 

 stages of the embryo, but is lost before the root is fully 



grown. * 



In the course of these investigations points of resemblance, 

 both in the prothallium and sexual organs were noted, that re- 

 called the corresponding points in Equisetum. So numerous 

 were these, that it led to a belief of a nearer relationship be- 

 tween the Equisetineae and Filicineae than is usually maintained, 

 and to warrant the possible union of the two classes into a group 

 opposed to the Lycopodineae. Van Tieghem 2 has called at- 

 tention to correspondences in the sporophytes of Equisetum 

 and Ophioglossum which confirm this view. It is even pos- 

 sible that this might be carried so far as to assume a common 

 origin for these two classes, distinct from that of the Lycopo- 

 dineae which in some respects recall rather the true mosses 

 than the liverworts. One great difficulty in dealing with the 

 Lycopodineae, and especially the Equisetineae, is that they are 

 degenerate forms which have lingered after their larger and 

 better organized kindred have disappeared, and it is difficult 

 to judge which are primitive and which secondary characters. 

 Certain it is, that the investigated species of Lycopodium 8 dif- 

 fer more from Equisetum, than does the latter from the ho- 

 mosporous Filicineae. Still we are not yet in a position to 



speak positively on this point. 



Of the true Ieptosporangiate ferns, the reasons already given 



1 Campbell: Annals of Botany, Vol. V, No. IQ, P 243- 

 * Unfortunately the paper was not accessible. 

 3 Treub: Etudes sur les Lycopodiacees, Ann. du Jardin botanique de Buiten- 

 zorg, Vols. 4, 5, 7. 



