THK FHESH-WATEH CYANOPHYCEÆ OF ICELAND 



299 



Poulsen who ahvays showed grcat intercst in my work on the Ice- 

 landic Algæ. 



Anabæna catenula iKiitz.) Born. et Flah. 



Bornet et Flahault, Revision IV p. 232. Wittr. et Nordst. Algae ex- 

 sicc. nr. 197. 



E. Icel. HallormstacMr, pool, temp. 11 » 28yg 1914 Fljotsdalur; rocky 

 wall over which water was trickling, faeing south-east '^^jf, 1914. — N. 

 Icel. Akureyri. Stream, on moss ^^7 1914. 



Area : Eur., N. Am., S. Afr., Alaska. 



According to Fritsch and Ricli (1913 p. 81) tliis species is a pro- 

 nounced summer-form in England which might suggest that it requires 

 a rather high temperature or perhaps an intense illumination in order 

 to thrive well. 



In Wittr. et Nordstedfs sample, cited by Bornet et Flahault (1. c ) 

 I found ripe spores 44 ^ in length, whereas the maximum according 

 to the specihc diagnosis is 30 // in length. The Icelandic specimens, 

 howeyer, were but possessed of spores 26 /( in length at their maximum. 



Anabæna catenula is an attached species which generally is found 

 among other piants in stagnant or slowly running water. Its occur- 

 rence on a dripping rock seems uncommon. 



Anabæna Jonssoni Boye P. n. sp. 



A. filis solitariis ad alias algas crescentibus, sæpe eva- 

 gmatis vel arcte vaginatis, vaginis ægre conspicuis, circa 

 heterocystas sæpe distinctis, hyalinis; trichomatibus 2- 

 2.5 // crassis, rectis vel curvatis, articulis brevicylindicis 

 vel sphærico-depressis, 1-3 /< longis, cellula apicali ro- 

 tundata; cellulis contentu granuloso sine pseudovacuolis 

 (»vacuolis aérogeniis«) farctis; heterocystis hexagonalibus, 

 2-2.5 ^ crassis, usque 4 // longis; sporis ab heterocy- 

 stis remotis, solitariis, cylindricis, apicibus rotundato- 

 truncatis, circiter 3-5 /< crassis, usque ad 15 ,» longis. 

 episporio lævi, hyalino. 



N. W. Icel. Lake. Botn in Geirjjjofsfjoråur (H J V 

 2^7 1915 temp. 10«. ^ • •; • 



This species, which I name after the collector is 

 closely related to A. catenula (Kutz.) Born. et Flah. and 

 A. mimitissima Lemm.; but I feel nevertheless justified 

 in establishing it as a new species as it is sufficiently 

 deviating from the latter species. It is specially distin- 

 guished by the form of the vegetative cells and the 

 heterocysts, whereas it bears close resemblance to A 

 minutissima Lemm in the dimensions. Finally, I draw attention to the 

 faet that the sample, m which it occurred, was preserved in formalin. 



Anabæna verrucosa Boye P. n. sp. 



A. trichomatibus rectis, vaginis sæpe conspicuis, arctis, hvalinis; arti- 

 culis cyl.ndncis, ad genicula constrictis, 3-4 // latis, 4-8 ^c longis; cellula 



20* 



Fig. 11. Anabæna 



Jonssoni n. sp. 



(X1200). 



