258 GENERA INCERTAE SEDIS [ch. 



partially sunk in the margin, while its habit resembles closely Dennstaedtia 

 adiantoides (Willd.) Moore {Syn. Fil. p. 55). The onus of comparison will 

 then fall especially upon the third species. 



D. Moorei was first found in a dense wood by the side of the Copenhagen 

 river, New Caledonia, and its habit should be viewed in relation to moist 

 shade. The creeping rhizome bears crowded leaves with a slender rachis, 

 bearing a broad deltoid lamina, thin but firm, pinnate below but pinnatifid 

 above: the two lower pinnae are themselves again pinnate or pinnatifid. The 

 whole affords a broad expanse with reticulate venation, as a rule without 

 included vein-endings. Both scales and hairs are present. The sori are usually 

 all marginal, seated on free vein-endings: but occasionally sori appear also 

 upon the upper surface, at the ends of small included veins. In either case 





\ 



Fig. 7^2. Two mature marginal sori of Deparia Moorei Hook. Enlarged. 

 (After J. M<^L. Thompson.) 



they are slightly stalked, and the indusium is cup-shaped (Fig. 752). The 

 sporangia are numerous, and long-stalked, with vertical interrupted annulus, 

 and the sorus is of the '^mixed" type. 



The axis contains a perforated dictyostele with an ample pith. The leaf- 

 gaps are very irregular in size and outline, as are also the numerous per- 

 of forations. The result is a stelar skeleton of a type generally resembling that 

 Dryopteris, but differing in detail (see Vol. I, Fig. 172). The leaf-trace consists 

 of four or five strands, typically four: two larger adaxial strands arise some 

 distance from the base of the gap, two smaller median strands from its base. 



The receptacle of the sorus arises normally from the margin, while the 

 upper and lower lips are of superficial origin, as in the Dicksonioid Ferns 

 (Fig. 753, A, E). The receptacle shows slight signs of a gradate sequence of 

 the sporangia, but almost at once it is followed by a mixed condition (C). 



