POLYSTICHUM ACULEATUM. 11 



general desire to maintain two species — aculeatum and angu- 

 lare — as distinct, but to omit the third or intermediate species. 

 The characters recommended by my correspondents are very 

 various, and would divide a series in a variety of ways ; hence 

 I feel reluctant to publish them. 



In the edition of 1844, about eight pages are occupied with 

 quoted descriptions of these ferns, more especially from the 

 writings of Sir J. E . Smith, Sir W. J. Hooker, Mr. Babington, 

 and Mr. Thwaites ; but on revising these for republication, and 

 studying them with the careful attention which the writings of 

 these botanists always deserve, I found that no impression 

 whatever remained on my mind as to the distinctness or other- 

 wise of the ferns : the ideas suggested were theoretical, and 

 rather psychical than physical ; speculations on the writers, 

 rather than on the objects concerning wliich they wrote. 



I must also observe that Professor Kunze, one of the highest 

 authorities on the species of ferns, published in the ' Flora ' of 

 June 14, 1848, an essay on this very subject. It was intituled, 

 " On three species of Ferns hitherto involved in miich confu- 

 sion, Aspidium lobatum, Sm., A. aculeatum, Sin., and A. 

 Braunii, Spenn." An abstract of this essay appeared in the 

 ' Phytologist ' (Phytol. iii. 455), and a translation in extenso was 

 published in the 1st and 2nd Nos. of the ' Botanical Gazette,' 

 but I believe all botanists consider the confusion to be rather 

 increased than diminished by these well- intended labours. If, 

 therefore, one of the greatest pteridologists has failed in eluci- 

 dating the matter, it seems scarcely probable that any eiforts of 

 a general botanist will accomplish that desirable object. 



The European range of this fern extends to every country ex- 

 cept Spain, where one would rather suppose it unobserved than 

 absent, since it occurs commonly throughout France, especially 

 in the South, and ascends the Pyrenees to the height of 2,500 

 feet. It is found in Asia, Northern and Southern Africa, and 

 North America : in the latter country it is extremely rare, but 

 perfectly identical with our British plant. 



