188 SUMMARY OF CURRENT RESEARCHES RELATING TO 



staktophil and aerophil formation, are described. The list contains 1*5 

 species and 34 varieties, of which 3 species and 12 varieties are new to 

 Sweden. 



Egyptian Fresh-water Algae.* — J. Brunnthaler gives a short list 

 of fresh-water algse collected by him during a three-and-a-half months' 

 stay in Cairo and Heliopolis in the spring of 1913. In a short intro- 

 ductory account of previous work on the subject, he gives a resume of a 

 paper by P. Kaufmann not generally known, having been published in 

 the Revue d'Egypte, not easily accessible. The paper in question deals 

 with the plankton which colours the Nile green in the last week in June 

 every year. Brunnthaler quotes the list of species comprising the plank- 

 ton with the diagnosis of the new species, Aphanizomenon Kaufmanni 

 Schmidle. As regards his own work, his collections were made in the 

 ditches and canals in the neighbourhood of Cairo and Heliopolis. The 

 flora is poor on account of the irregularity in quantity and movement of 

 the water. At the time of stagnation a flora arises, rich in individuals 

 but poor in species. A rich flora is also prevented by the quantity of 

 detritus, mud, etc., which come down with the water. Sixty-three species 

 are recorded, of which one is new, Characiopsis aegypticum. 



New Spirogyra.f — S. Langer describes a new species of Spirogyra, 

 S. proavita, which is remarkable for its method of copulation. The two 

 cells which are prepared to copulate each push out a prolongation, and 

 when these prolongations have reached a certain length they curl over 

 each other and unite, whereby hook-shaped canals are formed, such as 

 are described by Wood and Haberlandt. In that case, however, the canals 

 occurred as a rare and abnormal phenomenon. In S. proavita it is a 

 constant growth. The number of the spirals and the absence of swell- 

 ing of the fertile cells are distinguishing features of this species. It is 

 in some particulars allied to S. insignis Kiitz. and S. Hassallii Petit. 

 The author regards the hook-shaped canals as an interesting link con- 

 necting the section Salmacis with Conjugatae. 



Spirogyra tjibodensis.f — F. C. von Faber describes a new species 

 of Spirogyra, which is distinguished by the wrinkled cross-walls, the 

 apparent lack of gelatinous sheath, and the habit of the cells to spring 

 apart. The author investigated specially this latter peculiarity and 

 found that the cells became so turgid in consequence of active assimilation 

 that they burst the cuticle and fell apart. The membrane of these free 

 cells then became stretched, turgidly decreased, and in certain cells the 

 protoplasm contracted and spore-formation took place. If the brightly 

 illuminated filaments were cultivated in running water, this splitting did 

 not take place. A peculiar intertwining of the filaments always occurs 

 in brightly lighted filaments before the springing apart of the cells, 

 which points to the beginning of copulation. By experiment it is possible 



* Hedwigia, liv. (1914) pp. 219-25 (1 fig.). 



t Bot. Kozlemenyek, xii. (1913) pp. 166-9. See also Hedwigia, liv. (1913) 

 Beibl., p. 72. 



X Ann. Jard. Bot. Buitenzorg, xxvi. (1912) pp. 258-65. See also Bot. Centralbl., 

 cxxiii. (1913) p. 502. 



