THE GENUS DRYOPTERIS IN BRITAIN 



ecologically to marshy woods. D. dilatata is relatively little bound to water, and in 

 many parts of Britain is both commoner and hardier than the Male Fern, and like that 

 species it has been recorded from every county and vice-county in the British Isles. 



Some idea of the range of form exemplified by these three species and the hybrids 

 between them can perhaps be obtained from Fig. 54, which shows, not indeed the 

 whole plant, but the bottom pinna from a fully adult frond of the cytologically worked 

 specimens. The sources of material were as follows: D. spinulosa and D. dilatata have 

 been available in abundance from various localities in England, Scotland and Ireland, 







D. spinulosa ^n - 164- 



Fig. 55. Diagram to Fig. 53c. x 1500. 



D. crist3f-3 n- 82 

 Fig. 56. Diagram to Fig. 53^. x 1500. 



the particular specimens represented in Fig. 54a and e being from central Ireland. 

 D. cristata was at first only available in cultivation from a plant supplied to the late 

 Dr F. W. Stansfield by a dealer and believed to have come originally from Switzerland; 

 this has, however, latterly been supplemented by material from the Surrey plant kindly 

 supplied by the discoverer (Payne, 1939). Of the two hybrids the first (Fig. 54<:) came 

 from central Ireland, where it was found by Dr Praeger in company with the two 

 putative parent species. The second hybrid, D. uliginosa (Newman) Druce (Fig. 54^), 

 was supplied by the late Dr F. W. Stansfield from a continental specimen which, 

 owing to the excessive rarity of this type in Great Britain, has not yet been supple- 

 mented by one of British origin. 



The cytological uniformity which prevails throughout most of the 'spinulosa' complex 

 makes it at first sight easy to deal with all the species collectively. All three taxonomic 



69 



