THE MALE FERN DRTOPTERIS FILIX-MAS 



(3) The leaves are stiffer in texture than those of D. Filix-mas, though they become 

 more hke that species under shade conditions. Under normal conditions of exposure 

 their relatively slow rate of decay results in an unusually conspicuous hanging mass of 

 russet-coloured dead leaves, visible below the functional crown at all seasons of the 

 year. 



(4) One of the best characters to observe in |^^ ft^kA 

 the field, though, unfortunately, one which is Ofc^A 

 lost in a herbarium specimen, is the concavity of ^^ ^m ^ ^^^ 

 the frond when viewed from above. The tips and ^ m 



edges of the leaves curl upwards conspicuously wri ^ 



in a young frond and never quite flatten out in ^ ^ ^ 



an old one (cf. Fig. 29). In all other forms of the |^ % V A 



Filix-mas complex the pinnae are either flat or A ^ ^ ^M 



ve recurved edges. A* ^C^ •^ 



(5) Average size of the sori does not as a rule ^ ^ *"^y 



have recurved edges. A* ^C^ ^b 



exceed i mm. and is therefore smaller than in D abbrevi^^a ^ ^ 



D. Filix-mas. Oddly enough the spores are almost "' ^. , • 17- c 



' ^ ^ . . rig. 31. Diagram to explain rig. 30. 



identical in size with those of D. Filix-mas ^ j^^^ 



(cf. Figs. 39-40)- 



(6) There are numerous pale scales (ramenta) on the rachis. 



Though the existence of D. abbreviata as a distinct form has been known for over 

 a hundred years, there has been much controversy about its status. This illustrates 

 so well the way in which a question of taxonomy may be insoluble without cytogenetic 

 information that it may be instructive to quote the literature in some detail as an 

 example of a type of situation which will meet us repeatedly in later pages. 



In 1 81 5, Lamarck and de CandoUe described in their Flore Frangaise a small fern from 

 south-west France as ' Polystichum abbreviatum' in the foUowing words: 



'On pourrait, au premier coup-d'oeil, prendre cette espece pour une simple variete 

 de la fougere male, mais elle est de moitie au moins plus petite; ses pinnules sont plus 

 courtes, plus obtuses, et presque d'egale largeur dans toutes leurs etendues : leurs lobes 

 sont plus larges, plus courts et moins nombreux, et chacun d'eux ne porte ordinairement 

 a sa base qu'un seul groupe de fructifications, tandis qu'on en trouve plusieurs a la 

 base de chaque lobe dans la fougere rnale. 



'Cette plante a ete trouvee dans les Landes, par les C. Dufour et Thore.' {Fl. Fr. 11, 

 560.) 



In Great Britain it is generally considered to have been Newman who first equated 

 de Candolle's 'species' with a British plant from Ingleborough in Yorkshire (1844, 

 History of British Ferns, 2nd ed., p. 202), while expressing doubts regarding its specific 

 distinctness. Moore, in 1848 [Handbook of British Ferns, ist ed., p. 43), regarded the 

 Ingleborough plant as definitely a variety of Filix-mas and called it accordingly Lastrea 

 Filix-mas var. abbreviata. Newman accepted varietal status for it in the third edition of 

 his History (1854) and called it 'de Candolle's Male Fern, Dryopteris Filix-mas var. 

 abbreviata'. In 1855, however, G. B. WoUaston, whose knowledge of British ferns, in 

 Newman's words, 'infinitely exceeds that of any other botanist with whom I have ever 



47 



