THE GENUS DRYOPTERIS IN BRITAIN 



both its suggested parents are now known to be tetraploids. By virtue of its apogamous 

 reproduction it is not a single plant but forms local populations in several parts of 

 Germany, Alsace and Silesia, while a variant which has spread to Switzerland has 

 there been designated Aspidium remotumva.T. subalpina Borbas,* or sometimes Dryopteris 

 Borbasii Litard. 



I have not seen any material of the original Aspidium remotum A. Braun, but a plant 

 purporting to be var. subalpina from Switzerland was kindly presented to me by the 

 late Dr F. W. Stansfield, the lowermost pinna of which is represented in Fig. 60. This 

 agrees closely with Luerssen's Fig. 145 (Rabenhorst's Flora, 1889) of ^. remotum A.Br., 

 and the importance of giving varietal status to the Swiss material may perhaps be 

 doubted. Be that as it may, my specimen of 'subalpina' agrees with Dopp's remota in 

 being apogamous and approximately triploid. 



Fig. 59. The Windermere 'Lastrea remota\ from sections. X 1000. a. Meiosis. b. Two extreme focal 

 levels through a metaphase plate in a root with approximately 164 chromosomes, for comparison 

 with Fig. 61. 



Though Dryopteris remota in the continental sense cannot be claimed for Britain on 

 the evidence of the Windermere plant discussed above, there are nevertheless two other 

 records of single plants each found once and exterminated in the wild state by the act 

 of collection though maintained in cultivation, which place the matter in a rather 

 different light. These are ' Lastrea Boydii\ collected on the shore of Loch Lomond 

 at the end of the last century (see Stansfield, 1934; von Tavel, 1934) and at first 

 identified as L. remota from a general resemblance to the Windermere plant; and 

 another specimen found in central Ireland by Praeger in 1898 (see Praeger, 1909) and 

 also identified as L. remota. Both these finds have been available to me as spore descen- 

 dants of the original plants, 'Dryopteris Boydii' being presented to me by the late Dr 

 Stansfield and the Irish remota having been obtained from Dr Praeger in 1935. Pinnae 

 of both these plants are shown in Fig. 60, and their general resemblance to the con- 

 tinental material is at once apparent. Cytologically (Fig. 61) these plants also resemble 

 the continental material in being apogamous and triploid. 



* Cf. Luerssen (1889). 



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