ZOOLOGY AND BOTANY, MICROSCOPY, ETC. -3L 



Missouri Botanical Garden. After a discussion of the habitats, stability 

 of habitat characters, and analysis of habitats, she gives a systematic 

 enumeration of the 116 species recorded, together with some critical 

 notes. One species, Pitkophora Mooreana Collins, is new. The paper is 

 illustrated by good photographs of the various habitats in the garden. 



Analysis of Seaweeds.* — W. H. Barlow has drawn up some analy- 

 tical results made by him on dry plants of Fucus serratus, F. vesicidosus, 

 and Ascophyllum nodosum, collected at Padstow. In the case of 

 F. serratus the phosphoric acid was considerably higher than that found 

 in a Thanet specimen previously reported on by other investigators. 

 The total alkalis in the three species examined were found to be nearly 

 uniform. 



Saprophytism of Enteromorpha. j — E. Hayren writes on the sapro- 

 phytism of certain species of Enteromorpha. He has examined species in 

 the harbour of Helsingfors, and finds that E. clathrata and certain forms 

 of E. intestinalis may be regarded as " oligosaprob," while E.jlexuosa, 

 E. crinita, and certain other forms of E. intestinalis, are weakly " meso- 

 saprob." The presence of Enteromorpha in brackish or salt water leads 

 to the inference that the water is foul, an inference which is strengthened 

 by the fact that A. Steuer finds Enteromorpha growing near the entrance 

 of sewers. The author further discusses other " saprob " species in the 

 harbour of Helsingfors, which have been found there by Bergmann and 

 Klingstedt. 



Periodicity in Spirogyra.J — C. H. Danforth writes on the periodicity 

 of Spirogyra, with special reference to the work of Benecke. After a 

 short introduction dealing with previous work on periodicity in algse, he 

 gives an account of his own experiments, comparing them with those of 

 Benecke. That author worked with Spirogyra communis, and the 

 experiments of Danforth were made with S. setiformis, 8. longata, 

 S. Grevilleana, S. dubia, and S. porticalis. The result has been almost a 

 complete lack of conformity in so far as the question of zygospore 

 formation is concerned. After describing in detail the experiments 

 carried out, the author summarizes his results as follows : It appears 

 that there are specific differences as regards the reactions of filaments 

 and zygospores in the species studied, and that Benecke's conclusions, 

 based on the reactions of S. communis, are probably not of general 

 application, or are applicable only under very special conditions. Of the 

 five species investigated three failed entirely to give the expected results, 

 and a fourth failed in every case but one. The remaining species, 

 S. Grevilleana, seems to agree more closely with S. communis, but even 

 here the agreement is not complete. The existence of sexual strains, 

 such as occur in some of the moulds, seems to be suggested, but evidence 

 on this point is lacking. It is still possible that Spirogyra, like Dictyota, 

 is inherently periodic in its functions, although its periodicity may be 

 extensively influenced by the environment. 



* Journ. Board of Agric, xvii. (1911) p. 832. 



t Meddel. Soc. Fauna et Flora Fennica, xxvi. (1909-10) pp. 157-61; and 

 Hedwigia, Beibl. 1. (1910) p. (150). 



X Missouri Botanical Garden. Annual Report, xxi. (1910) pp. 49-59. 



