ZYGNEMACE.E. 81 



var. c. stagnale. Kirsch. 



Sterile cells '01 mm., 3 to 4 times as long. 

 Tyndaridea stag?ialis, Hass. Alg. 162, t. 38, f. 9. 

 Tyndaridea stagnicola, Hass. Ann. N. Hist. x. (1842) p. 42. 

 Jenner Fl. Tunb. Wells, p. 182. 



It will be seen from the above that this is a variable species, of which 

 two of the three varieties are British. These are by no means un- 

 common, often mixed with other filamentous algae, and can scarcely be 

 confounded with anything else, even when sterile. 



Plate XXX. jig. 3. a, portion of sterile thread X 400 ; b, portion 

 of fertile thread with zygospores X 400. Fig. 4, var. subtile, a, portion 

 of sterile threads X 400 ; b, conjugating threads and zygospores X 400. 

 Fig. 5, rar. stagnale. a, portions of sterile threads X 400 ; b, fertile 

 cells with zygospores X 400. 



Zygnema anomalum. (Hass.) 



Sterile cells equal, or nearly twice as long as broad ; cytio- 

 derni thick, lamellose. 



Zygospore globose, olivaceous (sporoderm distinctly punc- 

 tate ?). 



SIZE. Cells -025 mm. diam., with mucous sheath about 

 double ; zygospore '026 mm. diam. 



Tyndaridea lutescens, Hass. Alg. t. 38, f. 4. Dickie Bot. 

 Guide 296. 



Tyndaridea cruciata, Harv. Man. p. 141. 



Tyndaridea abbreviata, Hass. Ann. Nat. Hist. x. (1842) p. 43. 



Tyndaridea anomala, Hass. Alg. t. 38, f. 2-3. Jenner Fl. 

 Tunb. Wells, 182. Ralfs, Eng. Bot. Supp. t. 2899. 



In boggy pools. 



The British species is the Tyndaridea anomala of Hassall and Kalfs, 

 and not the Zygnema anomalum of Continental botanists, which species 

 has the zygospore produced in the conjugating canal. The following is 

 the original description published by Ralfs in the supplement to " Eng- 

 lish Botany " : 



" It forms large, dark green masses in shallow pools on heaths. The 

 filaments are stout ; under the microscope each is found to be enclosed 

 in a hyaline sheath, which extends on each side about half the breadth 

 of the coloured portion, and is always more or less waved or scolloped. 

 At first it is nearly even, but it gradually becomes more and more irre- 

 gular, and the conjugating specimens are almost denuded. The joints 

 of the filament are usually about equal in length and breadth, but 

 sometimes twice as long as broad. The endochrome is blackish green, 

 and at first quadrate, when it completely fills the joint, but its division 

 into two portions gradually becomes apparent until two stellse, but less 

 distinct than those in the other species, are at last developed, when con- 

 jugation takes place in the usual manner. The spores, which are 

 globular, are contained in the joints of one of the connected filaments. 

 Not uufrequently the tubular processes are themselves converted into 

 cells containing endochrome. 



" In its early state this plant is so different in appearance from the 

 other species, that at first sight its proper situation is scarcely appa- 



