497 



NEW AND RARE FRESHWATER ALG^. 



By G. I. Playfair, late Science Research Scholar op the 

 University op Sydney. 



(Plates liv.-lviii.; and eleven Text-figures.) 



In the following notes are embodied observations on a number 

 of new and rare freshwater alg?e, that have come under my notice 

 during the last few years. Of those mentioned, a little over two- 

 thirds of the new forms, and about half the others, are from 

 Lismore, the gleanings of 23 gatherings made during the summers 

 of 1916 and 1917: to be precise, from Sept. 16th, 1916, to May 

 Uth, 1917, and from Sept. 21st, 1917, to Feb. 10th, 1918. During 

 the colder months of May, June, July, and August, very little of 

 interest is to be found. The others are from older samples, also 

 locally obtained, or out of still earlier gatherings from Sydney. 

 In all, 66 new forms are described and figured, 28 being ad- 

 mitted to specific rank, 29 classed as variations, and 9 as forms; 

 una new genus is proposed. The figures are, of course, all drawn 

 from Australian specimens. 



Habitats. — The districts from which the various forms have 

 been obtained are purely of local interest, but more general value 

 attaches to the character of the habitat. The numbered gather- 

 ings, referred to, are accordingly classified as follows. Plankton : 

 80, 81, 90, 99, 100, 115, 121, 136, 258, 265, 266, 311, 316, 327, 

 328, 332, 340«, 347, 362. Out of weeds (practically plankton): 

 3, 26, 50, 158, 184, 189, 193, 272, 317. Mucous strata: 306, 

 323, 326. Ponds, lagoons, and swamps account for the remain- 

 ing twenty. 



One of these last, a swampy pool formed entirely by surface- 

 water, deserves special mention; during the two smnmers, it was 

 responsible for 30 out of the 64 new forms here described. The 

 samples which refer to it are 284, 286, 298, 302, 308, 311, 312, 



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