CLOSTEBIUM. 



/ 



191 



Genus: Closterium Nitzsch. 



37. Closterium didymotocum Corda, 1835; Ralfs, Brit. Desm. 1848, p. 168 



t. 28, f. 7; W. & G. S. West, Brit. Desm. 1904, p. 116, t. 12, f. 1-5. 

 Forma minor; long. 204/,; lat. 27^; lat. apic. 12/, (PI. xnr, fig. 18). 



Bab. — In the Kan-gyi at Mudon (No. 24505) 



38. Closterium Dian^ Ehrenb. Infus. 1838, p. 92, t. 5, f. xvn, 1-6; W. & 



G. S. West, Brit. Desm. 1904, p. 130, t. 15, f. 1-6. 

 Lat. 16/t. 



Bab.— Mansang near Hsipaw (No. 24193). 



39. Closterium incurvum Br£b. Liste. Desm. 1856, p. 150, t. 2, f. 47; W. & 



G. S. West, Brit. Desm. 1904, p. 136, t, 15, f. 28-30. 



Lat. 10-15/4 ; apicibus 50/* inter se distantibus (PI. xm, fig. 16). 



Hab.— Momauk, east of Bhamo (No. 21551) 



40. Closterium Venus Kiitz. Phyc. germ. 1845, p. 130; W. & G. S. West, 



Brit. Desm. 1904, p. 137, t. 15, f. 15-20. 



Var. cellulis minus curvatis, apicibus obtusioribus. 



Lat. 7*8; apicibus 54/t inter se distantibus (PL xm, fig. 17). 



Hab. — Mansang near Hsipaw (No. 24193). 



The outer margin of this small form only occupied 138° of arc, the curvature of the cell 

 thus agreeing more nearly with that of CI. parvuhm Nag. than that of CL Vmut. It is, 

 however, much smaller than any known forms of CI. parvuhm and there are only two pyreooids 



in each chloroplast. 



Wille has figured a Closterium from Nova Zembla (vide Wille, Ferskv. Alg. Nov. Semlj, 

 1874, p. 60, t. 14, f. 84) which he calls " CI. partuitm Nag. forma." The curvature of his plant 

 is, however, too great for CI. parvuhm, the apices are also more rounded, and there are only 

 two pyrenoids in each chloroplast. Like the Burmese plant, its characters appear to be partly 

 those of CI. Venus, but the apices are more obtuse. 



Another form very similar to the Burmese variety has been described and figured by Borge 



Boree Alg. erst. Regnell. Exped. II. Desmid. 1803, p. 79, t. 1, f. 24), but it 



f 



from Brazil {vide Borge, Alg. erst. Regnell. 



is of much larger size. Raciborski has also figured a similar but^ slightly larger form from 



Australia. (Racib. Desmidyja Ciastonia, 1892, p. 362, t. 



41. Closterium pulchellum W. & GL 8. West, Desm. Singapore, 1897, p. 158 



t. 8, f. 8-9. 

 Var. Burmense var. n. (PL xm, fig 

 Var. minus, cellulis diametro 6-7-plo longioribus, minus curvatis ; membrana 



achroa. 



Long. 38-58^; lat. 7-8-5 M ; lat. apic. circ. 2-2-7/*. 



ifci.-Mansang near Hsipaw (No. 24193). In swamp, Katha (No. 22677). 



Ann. Rot. Bot. Gakd. Calcutta Vol. VI 



