92 



Chlorophycece 



16 30 p.; fig. 33 D F) occurring attached to the shells of Limncea 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 Tremethick, Cornwall. D F, G. stagnalis 

 (West) Schmidle, from near Sutton, 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, 

 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. 



