93 



HARPIDIOID HYPNA OF YORKSHIRE AND DURHAM. 



WILLIAM INGHAM, B.A., 

 Organising Inspector of Schools, Haxby Road, York. 



The following' list contains the water-loving" Hypna only, which 

 prove so difficult to identify to students of mosses. I think it 

 well to place this list on record, for I have given special attention 

 to these ' water ' mosses, and have succeeded in finding- in York- 

 shire and Durham all the British species except one, and nearly 

 all the varieties. 



This list has a special value, because not only have the 

 mosses been kindly verified by H. N; Dixon, M.A., F.L. S., and 

 J. A. Wheldon, F.L.S. , but many of them have been examined 

 and brought up to date by Mons. Renauld himself. 



As we should have expected, there is a wonderful range of 

 varieties and forms among these water mosses, especially in the 

 case of H. aduncum and H. flilitans. 



On Coatham Marshes we have the various forms of H, 

 aduncum growing within close proximity to each other, and yet 

 varying so much as not to appear to be the same mosses. In 

 two of the Coatham forms the alar cells of the leaves are 

 incrassate, so contrary to the type of H. aduncum. Mons. 

 Renauld says these incrassate alar cells are accidental and due 

 to the semi-salt soil on which the mosses grow. 



The numbers after the habitats are those of the botanical 

 vice-counties. It is interesting to notice that the new form 

 diversifolia Ren. of H. aduncum occurs in two widely-separated 

 habitats, Selby and Coatham Marshes. 



In the case of Hypnum aduncum and H. Jiuitans, the nomen- 

 clature adopted in this paper is that by Mons. Renauld in 

 'Muscologia Gallica,' and by Renauld and Dixon in the 'Journal 

 of Botany' for August 1901. The order of Dixon's 1 Handbook 

 of British Mosses' has been followed with all the remaining 

 species. 



Hypnum aduncum Hedw. 



I. Group Typicum. 



1. Forma typicu. On the floor of magnesian limestone quarry, 

 Knottingley (63), the forma anomalci depauperata Ren. ; Clifton 

 Ings (62), on side of ditch, the forma depauperata, 'ad Group 

 Typicum accedens.' 



L902 March 3. 



