294 Physiologie. — Aigae. 



COULTER, J. M. and M.A.CHRYSLER, Regeneration \n Zamia. 

 (Bot. Gaz. Vol. XXXVIII. p. 452—458. fig. 8. Dec. 1904.) 



In mutilated stems o\ Zamia new shoots usually arise from 

 the vascular part of the central cylinder, but they may come 

 from the peripheral part of the wounded surface of the cortex. 

 In a few cases where the regenerated shoot Stands directly 

 over the central cylinder the whole cut end of the cylinder was 

 Seen to have taken part in this growth. This latter case is 

 an instance of complete regeneration of the lost part in the 

 strictest sense, and while the conditions which govern such an 

 occurrence are not certain^ it seems probable that it is more 

 likely to happen in young plants than in old ones. The origin 

 of new roots is just as variable. 



An attempt was made to determine the exact layer or 

 tissue which is capable of regenerating. The evidence pointed 

 to the conclusion that the power of regeneration, and also that 

 of developing adventitious shoots and roots, is present in all 

 meristematic tissue. The important meristematic tissue con- 

 cerned is the phellogen of the callus, and that which lies over 

 the region of the central cylinder is more successful than that 

 over the cortex. That polarity does not play a part in deter- 

 mining the nature of the structure produced is indicated by a 

 case where at one end of the mutilated stem two shoots and 

 a root were produced, while at the other a shoot was formed. 



H. M. Richards (New York). 



Emerson, Julia T., Notes on the blackening of Bap- 

 tisia tindoria. (Bull. Torrey Bot. Club. Vol. XXXI. p. 621 

 —629. Dec. 1904.) 



Finds blackening of leaves due to at least two oxidizing 

 enzymes. An oxydase, giving the blue coloration with gum 

 guaicum and a peroxidase which gives a deep blue with H« O2. 

 Both enzymes are destroyed with dilute Solutions of citric acid 

 or Na OH. H. M. Richards (New York). 



Newcombe, f. C, Klinostats andCentrifuges for Phy- 

 siologie al Research. (Bot. Gaz. Vol. XXXVIII. p. 427 

 — 434. fig. 3. Dec. 1904.) 



Description and specifications for klinostats or centrifuges, 

 propelled by water motor or electric motor. The speed of the 

 motors is reduced by means of an adjustable worm gear and 

 further by pulleys. More than one turntable may be attached 

 to a Single motor. H. M. Richards (New York). 



COLLlNS, F. S., Algae of the Flume. (Rhodora. VI. p. 229 



—231. Dec. 1904.) . 



The Flume is a well-known region in the White Mountains of 

 New Hampshire consisting of a narrow passage some fifteen to twenty 

 feet Wide with perpendicular walls^ through which a mountain stream 

 rushes. Dlrect sunlight seldom reaches it and it forms an ideal region 



