698 SUWMAIIY OF CUREENT RESEARCHES RELATING TO 



regardless of whether the respective pole is basal or apical. The author 

 finds, however, that if the basal pole be turned upwards it produces 

 much more protonema than the apical pole in a similar position. The 

 author concludes therefore that the power of regeneration at the basal 

 pole is stronger than that at the apical pole, and he denies that mosses 

 have true polarity, i.e. a distinct distribution of "organ-forming" 

 material. A correlation exists between the growing terminal bud and 

 the formation of protonema from rhizoids, inasmuch as protonema can 

 only be formed if the terminal bud be removed or checked in its growth. 

 After removal of the root-pole the formation of protonema takes place 

 plentifully. Fruiting and sterile stems behave alike as regards re- 

 generation. 



Thallophyta. 



Algse. 



(By Mrs. E. S. Gepp.) 



Characese of the Balkans.*^ — J. Vilhelm calls attention to the 

 scantiness of the Characeai hitherto recorded for the Balkan States. 

 Only twelve species had been made known for the region. He now adds 

 seven new forms, which he describes. They were collected in Bulgaria, 

 Montenegro, and the Athos Peninsula. 



Halicystis and Valonia.t — P. Kuckuck has made a minute study of 

 HalkysUs ovalis, its outer and inner structure, reproduction, germination 

 and development, mode of life, etc. His results are summed up as 

 follows : H. ovalis is a complete, unicellular, multinucleate member of 

 the Chlorophyceae, which, with its basal portion, bores into the 

 calcified crusts of Lithothamnion polymorphum. The chromatophores are 

 without pyrenoids, but contain starch. Even during the formation of 

 zoospores, which takes places in the upper part of the inflated cell, there 

 is no separating wall ; the protoplasm in the lower part of the cell 

 remains sterile. In some individuals large macrospores and small micro- 

 spores are formed, both of which bear two cilia at the apex, but no eye- 

 point. The macrospores are neutral, the microspores very probably 

 gametes. The zoospores issue through one or more holes. The groups 

 are sometimes roundish, sometimes band- or ring-shaped. The same 

 individual may go through as many as eight fertilisings ; fertilisation 

 occurring at the same time in all individuals of the same group, while 

 escape of the spores also occurs at almost the same time. After each 

 fertilisation, the holes close up and the empty spaces refill with chloro- 

 phyll. 



Kuckuck in the same paper makes some interesting and valuable 

 notes on three species of Valonia, V. macrophysa, V. utrkidaris, and 

 V. (Bgagropila. They are composed of several to many cells, and each 

 cell contains many nuclei. The chromatophores possess a large pyrenoid. 

 Valonia is always attached externally to the substratum. Besides the 

 daughter-cells and the swollen excrescences, not cut off from the main 



* Hedwigia, xlvii. (1907) pp. 66-70. 



t Bot. Zeit., Ixv. (1907) pp. 139-85 (1 pi., and figs, in text). 



