137 



" The Twenty-seventh Report of the Council of the Leeds Philoso- 

 phical and Literary Society at the close of the Session 1846-7;" pre- 

 sented by that Society. 



" On Conjugation in the Diatoinaceae," and " Further Observations 

 on the Diatoinaceae, with Descriptions of new Genera and Species,' 1 

 by G. H. K. Thwaites, Esq. ; presented by the author. 



Mr. Thomas Moore communicated a paper " On a Variety of Las- 

 traea Filix-mas found by him in the Neighbourhood of Guildford, 

 Surrey, in December last." (See Phytol. iii. 137).— G. E. D. 



On a Variety of Lastrtea Filix-mas. By Thomas Moore, Esq.* 



Whilst walking through a wood in the neighbourhood of Guild- 

 ford, in December, 1847, my attention was particularly arrested by a 

 remarkable fern, which I at first thought to be a species distinct from 

 any which I had previously seen. I was accordingly induced to ga- 

 ther one or two of its then half-perished fronds, with the intention of 

 examining them more closely at a leisure moment. On giving the 

 plant this further examination, I found it to constitute a very distinct 

 variety of Lastraea Filix-mas, apparently identical with examples 

 which I had observed in the herbarium of the Society, from King's 

 Cliff Valley, near Bridgewater, sent by Mr. Clark. Subsequently Mr. 

 Newman assured me it was the variety of that species which he had 

 figured at p. 197 of his ' History of British Ferns,' and mentioned at 

 p. 201 in these words : " This plant in habit and general appearance 

 much more nearly resembles Athyrium Filix-fcemina than the species 

 which I am now describing (Lastraea Filix-mas), but the scales of the 

 stem, the texture of the frond, and the character of the involucre (al- 

 though I have only seen it after the bursting of the capsules) are de- 

 cidedly those of Filix-mas, or a closely allied species." I had 

 supposed Mr. Newman's plant and my own to be the same, although 

 he does not very distinctly explain, nor indicate its peculiarities. 



What should form a species, or be considered a variety among 

 plants generally and ferns especially, is at present decided by no 

 very explicit rule ; and while this continues the case, it seems the 

 most desirable course to rank the plant under notice as a variety of 

 Lastraea Filix-mas, although very distinct as such from the common 



* Read before the Botanical Soeicty of London, 7th April, 1848. 



