92 



Cliloropliycew 



16 30 p.; fig. 33 D F) occurring attached to the shells of Limneea peregra. 

 Schmidle has recently given a short systematic account of the genus 1 . 



Fig. 33. A C, Gongrosira viridis Kiitz. (x500). A, from rocks, Lough Beg, 

 Ireland ; B and C, from rocks near Trernethick, Cornwall. D F, G. stagnalis 

 (West) Schmidle, from near Button, Cambridgeshire ( x 200). zg, zoogoni- 

 dangium. 



Genus Leptosira Borzi, 1883 2 . This genus is scarcely to be 

 distinguished from Gongrosira. The plants are aquatic, forming 

 very minute bright green cushions. The branches are torulose, N 

 the terminal cells being elliptical, doliform, or sometimes irregular 

 in form. The cell-contents are pale yellow-green in colour and 

 their structure is exceedingly difficult to observe. The zoogoni- 

 dangia are intercalary and usually consist of the modified, older 

 cells of the plant. The zoogonidia may germinate directly or they 



1 Schmidle in Berichte Deutsch. Botan. Gesellsch. 1901, Bd xix. 



2 Borzi, 'Studi Algologici I,' Messina, 1883. 





