NITELLA 623 



T. prolifera is recorded only for Oxfordshire (as above) of the border- 

 ing counties. 



WITEIiliA, Agardh, Syst. Alg. Introd. 27 (1824). 

 N. mucronata, Coss. et Germ. Fl. Env. Par. ed. i, 683 (1845). 



Chara mucronata, A. Br. in Ann. So. Nat. and ser. i. (1834) 351, and 

 in Flora, i. (1835) 52. 

 Groves, I.e. t. 210, 165. Syme, E. B. xii. 182, t. 1902. Nyman, 878, 

 Native. Lacustral. Ditches and streams. Very local and not 



permanent in its localities. July -September. 



First found in Berkshire by the author in September, 1892. See Bep. 



of Bot. Exch. Club, 395, 1892. 



1. Isis. In a small ditch which is fed by the Thames in the 



meadows between Godstow and the King's Weir, and in the 



River Thames in the same neighbourhood. 



In August of the same year I found it growing in great quantity in 



Oxfordshire in a small ditch bordering Godstow Nunnery, where 



it remained through the autumn and was visible through the ice in 



the winter. By the succeeding March it had entirely disappeared, 



nor since that time has it again been found there, but I have seen 



small patches of it in the river between Godstow and Medley. It is 



very remarkable that N. mucronata and Tohjpella intricata, which occur 



some seasons in such immense quantities over a limited area, should 



so completely disappear, as has been the case with the former species 



at Godstow, and with the latter at Marston in Oxfoi'dshire, and at South 



Hinksey in Berkshire. I have yearly, for seven years, visited the 



locality for T. intricata at Marston without being able to find a scrap, 



whereas in 1889 a wagon load might have been collected. In 1897 it 



has, however, reappeared. 



N. Tmicronata was first found in Britain by Dillenius near Thistleworth 

 [Isleworth] in Middlesex about 1720. Specimens and descriiDtion are pre- 

 served in Herb. Oxf. It was next recorded from a marsh ditch at West 

 Grinstead in Sussex by Mr. Borrer, and after a lapse of nearly half a century 

 was discovered by or in the river Ouse near Bedford, by my friend Mr. J. 

 Saunders and Mr. A. H. Davies. The discovery of it in Oxfordshire was 

 made by me in 1892, when I was showing a number of Extension students 

 the classic locality for AristolocJiia Clematitis near Godstow. In the following 

 month I found it in Berkshire, in a locality only about half-a-mile from God- 

 stow. Mr. H. Groves collected specimens from Godstow for his Exsiccata. 



N. mucronata is recorded for Oxfordshire and for Hampshire. 



N. translucens, Agardh, Syst. Alg. 124 (1824). 



Chara translucens, Pers. Syn, ii. 531 (1807). 

 Groves, 1. c. t. 210, 165. Syme, E. B. xii. 181, t. 1901. Nyman, 877. 

 Native. Lacustral. Ponds on peaty soil, very local. June-September. 

 First found in Berkshire by the author in 1887, and distributed 

 through the Bot. Exch. Club of that year. See Journ Bot. (1890; 68. 



