THE GENUS DRYOPTERIS IN BRITAIN 



reason for believing that the plant is likely to be found here though not yet diagnosed. 

 Further information about diagnostic characters, genetical affinities, geographical 

 distribution and appropriate name must, however, await further study. Enough has 



Fig. 64. Lowest pinna of a very large plant of the new diploid of Dryopteris dilatata 



from the Alps. Natural size. 



nevertheless perhaps been said to explain why taxonomists working on the alpine and 

 subarctic forms of the spinulosa complex have been less satisfied with the simple sub- 

 division into D. spinulosa, D. dilatata and D. cristata than have botanists working on the 

 lowland populations of more equable latitudes. 



78 



