186 DUBUN NATTJRAL HISTORY SOCIETY. 



Dr. Kinahan states that independent travellers have distinguished 

 these two forms in all parts of the world. This is scarcely accurate. In- 

 dependent collectors and botanists have brought Hymenophylla from all 

 parts of the world, and their species have been decided upon at home, 

 with all the assistance of the practised observers in the field. I was 

 well aware, and indeed stated, that both forms of Hymenophyllum had 

 occurred to me growing side by side in the south of Ireland : so I can 

 confirm Dr. Kinahan' s remarks on this point, rather than contradict them. 



From Dr. Kinahan's remarks, given in inverted commas, one might 

 gather that he goes as far as could be desired in the range to be given to 

 species ; for of course if, in travelling, we find gradational forms between 

 species, we are justified in uniting in one the extreme varieties, but there 

 is little trust to be placed in such a series of gradational forms, gradu- 

 ally running into one another ; nor is it necessary to prove that one can 

 be converted into another by culture ere believing their unity. 



Dr. Kinahan very justly criticizes my statement that as^. Timhridgense 

 occurred in Norway it could not be called a southern form. This was, I 

 confess, a careless statement, and I feel only too willing to withdraw 

 it ; but would suggest that there is some impropriety in calling a cosmo- 

 politan species a southern form, as also that the occurrence in the nor- 

 thern seas of species found in the lists of a southern Tauna would not 

 necessarily imply that the Flora of the shores of that same ocean partook 

 at all of a southern type. Assertion in matters of this kind is worse 

 than useless, and, if my memory serves me, even the mistake above al- 

 luded to was not made, as Dr. Kinahan inclines to think, as a statement, 

 but rather thrown out as a suggestion. 



Leaving the matter of the transverse ring to Dr. Harvey, it is now 

 time to lay before you the facts which lead me to adopt Mr. Bentham's 

 view of the union of these species, a view which will soon, I have no 

 doubt, be held, not in the doubting manner of some, but from conviction, 

 by at least eight- tenths of our practical botanists, both in the British Isles 

 and on the Continent To satisfy the President that the two species are 

 one, it has to be demonstrated that the aspect and habits of the plants are 

 altered by change of locality, and that the shape of the involucre varies. 

 To satisfy Dr. Kinahan, one must prove either that by any amount of 

 culture the one form can be converted into the other, or show a speci- 

 men having both forms of involucre on the same plant, or possessing in- 

 volucres of a mixed character ; or to prove that perfect specimens ever 

 did exist which caused a moment's hesitation as to which species they 

 belonged. 



I have had opportunities of seeing the unrivalled collection of Sir 

 "W. J. Hooker at Kew, and of examining there specimens of Hymeno- 

 phyllum Tunhridgeme and H. Wilsoni from almost every quarter of the 

 globe, and the united testimony of my eyesight and that of Dr. Hooker, 

 may satisfy the President when I state that nothing could well exceed 

 the variation of the habit of the two forms from various localities. Ex- 

 amination also showed a great diversity in the serration or toothing of 

 the involucEcs. In regard to 'Dr. Kinahan's first query, I cannot pre- 



