lO YORKSHIRE NATURALISTS' UNION. 



diatoms from near Doncaster, and followed up this action by 

 very kindly placing at our disposal a full and valuable list of the 

 diatoms of that district. In his list were enumerated about T25 

 species and many varieties, about a dozen of each of which were 

 additions to the flora. Of those localities vouched for by Mr. 

 Stiles 'Askern district' includes Askern, Wrancar Drain, and 

 Thorpe brickpond; 'Cusworth district' includes Cusworth, 

 Scawthorp and Bentley; and ' Hatfield district' includes Hatfield 

 West Moor, Hatfield brickponds, and Sandall brickpond ; 

 'Doncaster Town Water' is from Firsby, Thrybergh, and 

 Sheffield. 



Though we have made hundreds of journeys in quest ol 

 algae, we have not personally visited every district in Yorkshire, 

 yet we trust that the result of our efforts will form a substantial 

 basis-list, serving as a useful guide to future workers both in the 

 matter of the classification of these plants and in the species 

 they may expect to find. The classification adopted is the one 

 we think the most accurate and reliable, and great pains have 

 been taken to ensure that the nomenclature is as accurate as 

 possible. In a paper of this kind it is essential that some 

 synonyms should be given, as they are so useful to other workers, 

 especially when, as in many cases, they are the names under 

 which the plants have been at one time recorded for the county; 

 moreover, they are often the names (erroneous ones) found in 

 English text books. For these reasons as many synonyms have 

 been introduced as were considered to be necessary for the use of 

 those who are not well versed in the more recent phycological 

 literature. 



There will no doubt appear to be a dearth of localities for 

 many CEdogoniacese and Zygnemaceae, which are in reality widely 

 distributed. This is largely due to the fact that only those 

 species have been recorded that were in a satisfactory condition 

 for accurate identification, that is to say, those which possessed 

 ripe spores (oospores or zygospores). 



Trans. Y.N.U., i8g6 (pub. Aug. 1900). Bot. Series, Vol. 5. 



