THE FRESH-WATHR CYANOFHYCKÆ OE ICKLAND 267 



E. Icel. (ireen lunips among washed up Myriophyllum, pond in 

 bog near Grimsa, temp. 16*^ ^^/e 1914. — N. W. Icel. IsafjorSur, Arnar- 

 fjordur, Hariot (1893 p. 315\ Belloc (1894 p. 6). 



Arca: Eur., As., Am., Hawaii, Antarctic, Lappland, Færoes, Alaska, 

 Greenland. 



The specimens found at Grimsa were fairly large, up to 3 cm in 

 diameter. 



In close proximity to Sprengel's species Coccochloris stcignina, Al. 

 Braun (1863) placed two new species Aphanothecc j)r(isina and A. coerii- 

 lescens. A. Braun himself presumed it not improbable tliat both should 

 be considered as varieties of A. stagnina (Spr.) A. Br. Richter (1886) 

 examined these species and found that A. prasina and cocrnlescens could 

 not be kcpt apart and subsecpient authors agreed with liim on this point; 

 so that it ma}' be considered given that A. coenilescens = A. prasina. 

 I mysclf have examined the sample of A. coenilescens (Rab. Alg. Nr. 3) 

 cited by A. Br. and can confirm Richter's conclusions in so far as it is 

 impossible to distinguish A. cocrnlescens as a separate species or variet\\ 



A. prasina A. Br. is retained in the more recent algological literature 

 and considered occasionally as an independent species and at other 

 times as a variety of A. stacjnina. Al. Braun writes in Rab. Alg. Nr. 1572 

 the following: "Von beidcn (viz. A. prasina and A. cocrnlescens) durch 

 hellergriine Farbe, bestimmlere Abrundung der Massen und in der Gallerte 

 zerstreute Kalkkrystalle abweichend ist die åchte Coccochloris stagnina 

 Sprengel." At the same time he refers to Kiitzing Alg. aquae dulcis dec. 

 III nr. 29 as the type specimen. — Thus Al. Braun has 3 distinguishing 

 characters betwcen the two species, viz. 1) the colour of the colony, 



2) its form, 3) whether il contains crystals of calcium carbonate or not. 



Rabenhorst (Fl. cur. Alg. II p. 66, 1865) mentions nothing about crj'^- 

 stals, but adds a new distinguishing character between the two species, 

 viz. difference in size between the cells, i. e. presupposing those in A. 

 stagnina to be smaller than those in A. prasina. Richter (1886), however, 

 on the basis of exsiccata investigations, arrived at the conclusion that 

 no difference in size between these two species could be demonstrated; 

 he therefore distinguishes them by the three other characters, viz. 

 1) presence or absence of cr3'stals of calcium carbonate, 2) colour, 



3) greater or lesser regularity and solidit)' of the colony. The latter 

 feature (solidity) is, however, a new character advanced by Richter, and 

 in certain authors this becomes later the principal distinguishing character. 

 Richter founds his statement on a "Hcrbarnotiz" bj' A. Braun which is un- 

 known to me. But there is an obvious discrepancy between Richter's words 

 regarding A. prasina in his treatise in Hedwigia (1886 p. 254) in which 

 he says: "Gallertklumpcn . . . aus mehreren Stiicken bestehend und leicht 

 zerfallend". and the inscription on the label belonging to the very sam- 

 ple which he deals with in the treatise (Phycotheca univers. Nr. 91). It 

 reads: „Kugeln von festerer Consistenz und rundlich-eckigem Umfang". 

 The specimens in the sample verify the last statement. 



Lemmermann (1910 p. 71) is in accordance with Richter's statement 

 on the label of the sample when he, with regard to A. stagnina, writes: 

 "Lager mchr oder weniger kugelig, leicht in Stiicken zerfallend", and 

 with regard to A. prasina: "Lager . . . nicht so leicht in Stiicke zerfal- 



18* 



