342 



ON GALLITRICHE OBTUSANGULA, Le Gall, AS A 

 BRITISH PLANT. 



By a. G. More, F.L.S., M.E.I.A. 



Callitriche obtusangula was first distinguished by Le Gall in. his 

 'Flore du Morbihan ' (1852), and has since been recognized by several 

 writers on the botany of the north and north-west of France. In the 

 new edition of ' English Botany,* Dr. Syrae mentions it as a sub- 

 species of Callitriche verna, likely to be found in Britain. I have long 

 had in my herbarium some specimens of a Callitriche, gathered in the 

 Isle of Wight so far back as 1860, and which at the time I was unable 

 to refer to any of the then described British species ; and it was only 

 last year when passing through Loudon that I had an opportunity at 

 the British Museum of comparing my plant with authentic examples of 

 C. obtusangula, published in Billot's ' Exsiccata ' (n. 1191), when 

 I was enabled to satisfy myself that I had gathered C. obtusangula in 

 the Isle of Wight. 



In the size of the fruit and in the general habit of growth C. obtusan- 

 gula closely resembles C. stagnalis {platycarpa), with which, indeed, 

 it was at once contrasted both by Le Gall in his original notice and 

 in Billot's ' Archives,' and of which it may be only a form produced by 

 the nature of the locality ; but Dr. Boswell-Syrae, following Hegelmaier, 

 places it nearer to his subspecies C. vernalis. It is on the shape of the 

 fruit that the distinctive characters of C. obtusangula are founded ; 

 this is less compressed, and the angles of the lobes, instead of being 

 winged ns in C. jjlatycarpa, or keeled as in C. verna, are rounded. 



C. obtusangula occurs in many localities along the French shores of 

 the Channel and Atlantic Ocean, in Normandy, Bretagne, and Poitou. 

 It has also been found in Belgium, Sardinia, and Sicily. 



The following is a description of the plant as found in the Isle of 

 Wight, preceded by references to the publications in which it is 

 noticed. 



C. obtusangula, Le Gall, Flore du Morbihan, p. 203 (1852) ; Billot, 

 Archives de la Flore de France et d'AUemagne, p. 295 (1854), et 

 Exsicc. Cent. xii. n. 1191 ; Le Jobs, Plantes Vase, de Cherbourg, 

 p. 51 (1860) ; F. Schultz, Herb. Normale, n. 655 ; Lebel in Me'm. Sc. 

 }sat. Cherbourg, vol. ix. p. 175 (18G3) ; Mabille, Cat. des Plantes de 



