THE ANATOMY AND AFFINITY OF DEPARIA MOOREI, HOOK. 855 



Deparia prolifera as the more primitive, Deparia Moorei as the derivative, of these 

 two allied species. 



The mere anatomical facts would not preclude the phyletic position adopted 

 by Diels and Christensen for Deparia, but the normal position of origin of 

 the sorus is distinctly against it. It has been shown in the above pages, from 

 observation of the earliest stages, that the sorus of Deparia Moorei is normally 

 of marginal origin. The actual margin of the leaf, with its marginal initials, is 

 involved in forming the receptacle. In fact the relations are exactly those demon- 

 strated by Bower for Dicksonia, Saccoloma, Davallia, and others of the series 

 " Marginales." This in itself would appear sufficient to rule out any direct 

 affinity for Deparia with Athyrium or Aspidium, which belong to the series of 

 the " Superficiales." 



But it may be objected that certain of the sori of Deparia Moorei are superficial, 

 and hence that the distinction between those alternative series breaks down in the 

 very species which is the subject of this paper. 



Those who attach weight to this objection must take into account the great 

 constancy of the distinction between those alternative series as stated by Bower. 

 If this is fully realised, it will then appear probable that the occurrence of superficial 

 sori in Deparia Moorei is a late and isolated example of departure from phyletic 

 habit, which is liable to occur under special conditions in isolated cases. Such 

 examples cannot be held to overthrow the conclusions derived from a wide study of 

 more primitive types. 



The conclusion may then be stated, that the consensus of the morphological 

 characters described in these pages — in so far as they are indices of physiological 

 advancement — place Deparia Moorei high in the scale of Ferns, and point for it a 

 Davallioid affinity in the sense briefly explained by Bower in The Origin of a Land 

 Flora, and recently more clearly indicated by him in " Studies in the Phylogeny of 

 the Filicales," iii, Annals of Botany, July 1913. 



EXPLANATION OF TEXT-FIGURES. 



Figs, i-viii. Part of a series of transverse sections of a sturdy axis showing the most advanced 

 dictyostele found. x 6. 



Figs, ix-xxvi. A series of eighteen sections into which the apical part of an axis was cut ; this is part 

 of the series from which the reconstruction (fig. 40) was made. 



This series illustrates the most reduced stellar condition found, x 6. 



N.B. — Stele is represented in black ; leaf-trace is shaded ; root is mottled. 



Figs, xxvii-lvi. A series of diagrams indicating the course of the vascular system from the top of the 

 rachis to the tip of a pinna. x 12. 



