310 Algae. 



inclusive, and found to average 1.47 for each degree centigrad rise 

 in temperature. This average temperature coefficient corresponds 

 closely with that found by Goodspeed (1.27) whose experiment 

 involved the use of much higher temperatures for barley grains. 



Jongmans. 



Child, C. M., Axial susceptibility gradients in Algae. (Bo- 

 tan. Gazette. LXII. p. 89^-114. 1916.) 



In 14 species of marine algae, including 10 species of Rhodo- 

 phyceae, 2 of Phaeophyceae, 1 of Chlorophyceae, and 1 of Cyanophy- 

 ceae, a more or less definite gradient in susceptibility to KCN exists 

 in the vegetative axes, and in several species in other parts also; 

 the susceptibility being greatest, at least during growth and deve- 

 lopment, in the apical region and decreasing basipetally. 



Since extended experiment with the lower animals indicates 

 that the degree of susceptibility to cyanides and to many other 

 agents and conditions is in a general way, and within certain 

 limits, a rough measure of metabolic activity or of certain funda- 

 mental metabolic process, probably primarily the oxidations, these 

 axial differences in susceptibility in the algae are regarded as indi- 

 cating the existence of axial metabolic gradients. If this conclusion 

 be correct, the axis in these simple plants is identical with the axis 

 of the animal organism in this respect. 



The relations of physiological dominance and Subordination 

 of physiological isolation and of differentiation to metabolic gra- 

 dients, are briefly considered. Jongmans. 



Howe, M. A„ A note on the structural dimorphism of 

 sexual and tetrasporic plants of Galaxaura obtusata. (Bull. 

 Torrey Botan. Club. XLIII. p. 621—624. 1916.) 



The author is convinced that the „Spissae" and „Cameratae" 

 characters of this calcified red alga do not offer a proper basis for 

 subgeneric groupings of species as supposed by Kj eil man, who 

 first accurately pointed out these characters. They merely distin- 

 guish the gametophytic and sporophytic phases in the life history 

 of a Single species. Jongmans. 



Roe , M. L„ The development of theconceptaclein Fucus. 

 (Botan. Gazette. LXI. p. 231-246. PI. 14-17. 1916.) 



The conceptacle originates as a slightly modified continuation 

 of the extemal layer of the thallus, being Segments of the apical 

 cell whose basal portions are constantly meristematic and never 

 entirely breaking down. 



The hairpit is a juvenile stage of the conceptacle, the sex Or- 

 gans appearing in the same cavity as the mature hairs, but after 

 their loss. 



A distinct phylogenetic series is seen in advance from conti- 

 nuous patches of hairs and reproductive bodies, to scattered sori, 

 to scattered conceptacles, and finally to apically placed conceptacles 

 or to conceptacles on specially developed side branches. All of 

 these structures originate through modification of the superficial 

 layer of the thallus. Jongmans. 



