196 SUMMARY OF CURRENT RESEARCHES RELATING TO 



regarded as a primitive form of kelp. A variety is described, var. 

 perlonga, which is often more than a metre long, while the type appears 

 not to exceed 50 cm. in length by 25-90 mm. wide. Cryptostomata 

 are absent even on young plants, as are also mucilage ducts. The sorus 

 is mostly irregular in shape, and sometimes it takes the form of five (or 

 less) fructiferous stripes. Both sides of the lamina are fertile. It 

 differs from Phyllaria in having no cryptostomata, and from Cymathere 

 in having a flat, not a folded, lamina. The author transfers to this 

 genus, Laminaria solidungula J. Ag. and L. yezzoensis Miyabe. 



Colpomenia sinuosa.* — C. Sauvageau addresses the Scientific Society 

 of Arciichon on the sul)ject of the possible invasion by this alga of the 

 oyster beds in the Basin of Araichon. He speaks of the general condi- 

 tions necessary to the growth and spread of the species, and the danger 

 of introducing it by spores, or otherwise, from those places where it 

 has already proved so disastrous to the oyster culture. He considers 

 that the optimistic view of Fabre-Domergue as to the eradication of 

 the plant is not justified. Other algse which are prejudicial to the 

 oyster beds are treated of, and the suggestion is made of introducing 

 herbivorous Gastropods at Arcachon, as has been done at Sables- 

 d'Oloune, in order to keep down certain richly-growing species of algae. 



Cladostephus verticillatus.f — C Sauvageau has investigated mi- 

 nutely the history and identity of Cladostephus vertidllatus. He comes 

 to the conclusion that the real author of the species is Lyngbye, who 

 designated by this name a plant which was a variety of the type at a 

 time when the limits of the species were not sufficiently defined. The 

 elder Hooker at a later date gave this name to the type, while C. Agardh, 

 who created the name originally, used it to denote an alga belonging tO' 

 a totally different group. The present author therefore considers that 

 priority should be accorded to Lyngl)ye and the species known as G. 

 vertkiUaius Lyngbye. He gives the full synonymy of C. spongiosus and 

 C. verticillatus, as well as that of his own variety, 2J0'tentissima of G. 

 verticillatus. He adds a list of names which must be struck out from 

 the synonymy of either species. 



Formation of Gametes in Bryopsis.J — H. Freund gives the result 

 of some experiments on the conditions which lead to the formation of 

 gametes in Bryopsis plumula and B. muscosa. He quotes Oltmann's 

 description of the different forms of male and female gametes, as well as 

 the process of copulation, and then describes the treatment to which 

 he subjected the plants, with the corresponding results. Finally, he 

 adds a few details on the morphology of Bryopsis. 



Botryodictyon and Botryococcus.§— 0, W. F. Carlson has made a 

 careful comparison of Botryodictyon elegaus Lemmermann and Botryo- 

 coccus Braunii Kiitz, and finds that they are identical. He believes that 

 B. elegans is only a Botryococcus colony, and he gives his reasons for 

 this conviction. The position of Botryococcus among the Chlorophyceae, 



• Soc. Sci. Arcachon, ix. (1906) pp. 35-49. t Tom. cit., p. 30. 



X Beih. Bot. Centralbl., xxi. (1907) pp. 55-9. 



§ Botaniska Studier tillagnade. Upsala : F. R. Kjellman, 1906, pp. 141-6 (1 pi.). 



