854 MR JOHN M'LEAN THOMPSON ON 



a conclusion also adopted by Christensen in his Index Filicum. In light of the 

 facts detailed in these pages, — and especially those facts relating to the development 

 of the normal marginal-sorus of Deparia Moorei — I am unable to agree with the 

 conclusions arrived at by Christ, Diels, and Christensen, regarding the phyletic 

 position of this Fern. 



In the first place, in attempting to place Deparia Moorei systematically and 

 phyletically, a comparison with Deparia prolifera — the best known and most 

 distinctive species — is ready to hand. The relationship of those two ferns has been 

 generally recognised, and the facts advanced in the above pages do not cast any 

 doubt on its validity. It may be held to be a true affinity. This opinion is retained 

 notwithstanding that Christ places Deparia "prolifera in the genus Athyrium, and 

 Deparia Moorei in the genus Aspidium, with special comparison with Aspidium 

 cicutarium. But the similarity in normal position and in construction of the sori 

 would appear to leave no room for doubt that Deparia prolifera and Deparia 

 Moorei should be placed in the same genus. The differences between these species 

 are significant. Deparia prolifera has open venation, and long leaves with numerous 

 and relatively narrow pinnae. Its sori are constantly marginal ; and a general com- 

 parison with the Davallioid ferns appears ready to hand. Deparia Moorei has, 

 however, a reticulate venation, and relatively few broad pinnae, while the sori are 

 mostly marginal in origin, though occasionally isolated sori appear upon the upper 

 surface of the leaf. When the locality specified by Charles Moore for Deparia 

 Moorei is recalled, " in a dense wood by the side of the Copenhagen River, New 

 Caledonia," the conclusion seems probable that in Deparia Moorei we see a species 

 specialised for life in moist shade. A similar state is seen in Hypoderris as com- 

 pared with its ally Woodsia (cf Bower, Studies in Phyl. of Filic, ii, pp. 306-308). 

 In both Deparia Moorei and Hypoderris the pinnation appears to have been 

 simplified, and the venation to have become reticulate. A somewhat similar state 

 is seen in Onoclea sensibilis, as compared with Struthiopteris (Metteuccia). Similar - 

 comparisons might be drawn from other genera. Such comparisons point to the 

 conclusion that in Deparia Moorei we see a derivative type, advanced from the 

 condition seen in Deparia prolifera. The advance in the lamina has been in relation 

 to conditions of dense shade. Such a conclusion also accords with the more advanced 

 anatomical state of the rachis of Deparia Moorei as compared with that of Deparia 

 prolifera. As regards the soral position, Deparia Moorei normally shares with 

 Deparia prolifera the marginal origin, as in Davallioid types. The occurrence of 

 occasional sori on the upper leaf-surface in Deparia Moorei is also held to be a 

 derivative state, that is, a result of bodily transfer of the factors of soral initiation 

 (whatever these may be) from the normal marginal position to points upon the 

 surface of the lamina. An analogy for such a bodily transfer is seen in the case of 

 Polyslichum anomalwm, where the sori, normally on the lower surface, are developed 

 on the upper surface of the leaf. The result of those comparisons is to recognise 



