DESMID FLORA OF DARTMOOR. 261 



Dartmoor bogs. For some time I confused it with C. 

 sphalerostichum Nordst. until a careful examination of 

 empty cells changed my opinion. Professor G. S. West 

 says of a drawing, " Probably C. furcatospermum.^^ 



(236) C. punctulatum var. granulusculum (Roy and Bissett) 

 West. The authors of the British Desmidiaceae state 

 that they have never seen any specimens of this variety. 

 I have had from Metherall and Postbridge gatherings 

 several empty cells which exactly agreed with the descrip- 

 tion and figure given from Roy and Bissett in West's 

 monograph, and it certainly seems an equally distinc- 

 tive variety with Klebs' C. functulatum var. rotundatum. 



(162) Cosmarium bipunctatum var. subrectangularis West. A 

 Hebridean variety {Teste, Professor G. S. West). 



(259) Cosmarium speciosum Lund. This species from Lydford 



Gorge, 



(260) and also its variety Rostafinshii have a doubtful claim to 



be considered as Dartmoor desmids on account of their 

 habitats, but are included in order that they may be 

 recorded for the county. (See ante, Closterium Malin- 

 vernianum.) 



(177) Cosmarium crenatum forma Boldtiana (Gutw.) West. 

 Apparently a very rare form only recorded by Roy and 

 Bissett from Scotland. 



(291) Xanthidium armatum var. irregularis West. An Irish 

 variety which occurs very infrequently in several of the 

 older Dartmoor bogs. 



(294) Xanthidium Robinsonianum Arch. This rare desmid 

 occurred in profusion in a small moor pool on White 

 Horse Hill at an altitude of about 1,800 feet. A few 

 specimens were also obtained from one of the bogs at 

 Postbridge. 



Literature Cited and Consulted 



1. Parfitt, E. : Devon Freshwater Algae. Transactions of 



the-Devonshire Association, vol. xviii. 1886. 



2. Bennett, A. W. : Freshwater Algae and Schizophyceae 



