SPIROGYRA. 



185 



2150 



Bab.— Near the river at Bhanio (No. 



This species is Dearest to V. sericea Lyngb., but the filaments are 



are larger 



are 



not rostellate, the 



more slender, the oogonia 



are 



Order: CONJUGATE. 



Family: ZYGNEMACE£. 



Genus: Zygnema Ag. 



15. Zygnema spontaneum Nordst. Alg. aq. dulc. et Char. Sandvic. 1878, p. 17, t. 1, 



f. 23-24; W. & G. S. West, Welw. Afric. Freshw. Alt: 1897, p. 40. 



Crass, cell, veget. 21/z; crass, cell, fruct. 



zygosp. 19-25//, (PI. x 



9 



fig. 



5). 



22-24/*; long. 



zygosp 



21-2-V; lat, 



Hob 



In springs on the river bank at Bhamo (N 



21501) 



Z. spontaneum Nordst. is essentially tropical in its distribution, 



d there appears to be a 



certain amount of confusion with regard to its identity. The specimens originally described by 

 Nordstedt from the Sandwich Is. possessed only aplanospores, but in 1897 we described the 

 zygospores from W. Africa. About the same time Schmidle described from Australia what he 



considered to be a new species Z. Hi 



but the only differences between his plant and 



Z. spontaneum are in its lateral conjugation and in the position of the zygospores in the 

 conjugating-tube. The wall of the zygospore is scrobiculate exactly as in 2. spontm urn, mid 

 Schmidle's plant is possibly a form of that species with a different type of conjugation. 



The appended table of measurements is for closer comparison of the different forms of 



■ 



Z. spontaneum with Z. Heydriehi Schmidle (Entwick. Zygn. u. Calothrix, 1897, p. 169, 170, t. C, 

 f. 5-7, 10, 11): 





Crass, cell. 



veget. 



Z. spontaneum 



Sandwich Is 



Crass, cell, 

 fructif. 



lat. : long. 



long, zygosp 



• • • 



14-18 



P 



Z. spontaneum 



W. Africa 



• •f 



# • ■ 



Z. spontaneum 



Burma 



16- J 8 



P 



20-24 



P 



19-25 



P 



• • • 



21 



P 



1 : 1} 



18-21 



P 



1 : l.}-4 



(aplanospores) 



24-31 ij, 



lat. 



zj-gosp. 



16-21 



P 



(aplanosporeit) 



21-24 





22-24 



P 



Z. Heydriehi 



Australia 



• •• 



- • • 



20 u 





1 : 2-3J 



1- li-3* 



21-25/* 



P 



19-25 



32 



P 





P 



26-28 



P 



Sterile species of Zyg 

 and from Kyauktaga in 



were observed from near the river at Bhamo (N 



2 1 503) 



th 



Peg 



disti 



22124) 



Geois: SpirGgyra Link. 



16. Spirogyra gracilis (Hass.) Kiitz. Spec. Alg. 2849, p. 438 j Petit, Spirogyra 



Enyir. Paris, 1880, p. 15, t. 

 Zygnema gracile Hass. 



f. 



8. 



Ann. Roy. Bot. Gard. Calcutta Vol VI. 



