Algae. 59 



FRITSCH, F. E., S t u d i e s o n Cyanophyceae. (The New Phyto- 

 logist. Vol. III. No. 4. April 27, 1904. p. 85—96. Text 

 Hg. 76.) 



The author proposes to publish a series of papers under 

 this title, of which the present communication is the first; it 

 deals with „Some points in the structure of an Anabaena". 

 The plant examined grew in a tank at Kew and was remar- 

 kable for the abundant occurrence of heterocysts. These were 

 not much larger than the ordinary vegetative cells and were 

 sometimes even smaller. They developed from the vegetative 

 cells and were mostly to be recognised at an early stage. Two 

 kinds were observed : terminal ones of a spherical shape, flatte- 

 ned on the side towards the vegetative cells; and intercalary 

 ones more or less barrel-shaped and flattened at each end. A 

 description of the development of the heterocysts is given which 

 scarcely agrees with that of Brand which was founded chiefly 

 on Nostoc commune and Tolypothrix. In older filaments of 

 Anabaena Fritsch finds as many as four terminal heterocysts 

 side by side at one extremity of the filament, and in such cases 

 the distal heterocyst is often the most fully differentiated. The 

 effect on these bodies of various staining reagents is described, 

 and the signification of heterocysts to the plant. The author 

 finds that cyanophycin-granules are present in the vegetative 

 cells of young plants, but in older stages these granules are 

 no longer present, but similar granules are seen in the hetero- 

 cysts; indicating that a movement on the part of the granules 

 takes place from the vegetative cells to the heterocysts. It is 

 therefore suggested that the heterocysts are recipients of reserve 

 substances — an organ for storing up the contents of neigh- 

 bouring vegetative cells, when these become exhausted, owing 

 to unfavourable externa! conditions or to active spore-formation 

 in the central, portion of a filament. In the case of centripetal 

 spore-formation, as in Sphaerozyga, it is possible that the 

 function of the heterocysts would be taken over by the inter- 

 calary ones. As regards Brand's Observation of the germi- 

 nation of the contents of heterocysts, it Stands isolated ; but the 

 author considers that these bodies may be the remnants of 

 important reproductive organs of the Cyanophyceae whose 

 functions have been now in great part taken over by the spores; 

 and the failure to confirm Brand's Observation may lie in 

 the fact that very extreme conditions may be necessary to cause 

 the heterocyst to revert to its former function and these extreme 

 conditions but rarely occur. E. S. Gepp-Barton. 



Gepp, Ethel S. , „Chinese marine algae". (Journal of 

 Botany. Vol. XL3I. No. 498. June 1904. p. 161 — 165. 

 PI. 460.) 



Alist of 27 algae from Wei-hai-wei and S wato w including 

 two new species, Chordaria /Irma and Ceramium Boydenii. 



