xxxix] 



PELLAEA 



83 



The sporangia are of superficial origin, arising near to the margin, and 

 opposite to the vein-endings: they show no regular or characteristic 

 sequence in their appearance. The margin itself is reflexed and indusioid 

 (Fig. 636, B, F)\ in P. intramarginalis (Klfs.) J. Sm., a strong tissue-growth 

 at the point of the greatest curvature forms a flange of tissue, comparable in 



Fig-637. Vascular system oi Pellaea rotundifolia (Foist.) Hook., 

 showing the departure of two leaf-traces (L.T.), and their rela- 

 tion to the solenostele of the axis. (After Gwynne-Vaughan. ) 



position to that so largely developed in Blechnnm : it also finds its parallel in 

 Kaulfuss' old genus Cassebeera, now merged in Chezlanihes, and apparently 

 also in C. lendigera itself These developments, which are variable in 

 occurrence and extent, may be held as a natural consequence of the region 

 of greatest curvature offering the least resistance to growth from within. 

 The result is the feature which suggested the specific name (Fig. 638). 

 The sporangia themselves are of an ordinary Leptosporangiate type. The 

 annulus is almost vertical, but it does not extend down to the insertion of 

 the stalk. The spore-counts for P. falcata (R. Br.) Fee show a typical 



Fig. 638. Vertical section through i\i&yom\g'iQx\\^oi Pellaea intra- 

 marginahs (Klfs.) J. Sm., showing the superficial origin of the spor- 

 angium, the indusioid margin and the flange. ( x too.) 



6-2 



