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THE DESMID FLORA OF A TRIASSIO DISTRICT. 



By G. T. Harris. 



Communicated by the Hon. Editor. 



{Read June 8th, 1920.) 



The district dealt with in this paper is situated entirely in East 

 Devon, between tlie estuary of tlie Exe on the western side and the 

 estuary of the Axe on the eastern side of the district. It is in 

 Watson's phyto-geographical district V.C.3, and in the Honiton 

 Division (5) of the county of Devon, as divided by Mr. W. P. 

 Hiern for botanical references (2), and which has been adopted 

 by the Botanical Sub- Committee of The Devonshire Association. 

 Beyond a few records by E. Parfitt (1) of the commoner species 

 from Woodbury Common no published records appear to have 

 been made. W. and G. S. West's records from Devonshire (3) 

 appear to be altogether from the district west of the Exe estuary, 

 Dawlish, Torquay and parts of Dartmoor (principally the 

 eastern fringe) ; and Joshua's (4) were probably more or less 

 from the same district as those of Bennett (5) : the Hajrtor and 

 Bovey Tracey. The portion actually collected over reached to 

 the Exe River in the west, between Topsham and Countess 

 Weir, nearly to the Axe at Seaton in the east, and to Honiton 

 and Broadhembury in the north ; an area roughly of about 

 160 square miles. But the principal collecting was done within 

 much narrower limits, being a small portion bounded by Wood- 

 bury Common in the west, Weston Mouth in the east, and 

 Broad Down near Farway in the north, this restricted area 

 corresponding with the district collected over when engaged on 

 the Moss Flora of the district (6) . It is from this smaller portion 

 (about five square miles) that the whole of the records in the 

 present paper have been compiled. The area is a flat tableland 

 sloping gradually from an elevation of about 885 feet in the northern 

 portion to 400 and 500 feet in the southern, and is deeply ex- 

 cavated into valleys and combes by the rivers Axe, Sid and Otter 

 with their numerous tributaries. The flat hill-tops are principally 

 beds of chert and flint embedded in a stiff yellow marl, below 



