218 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Various methods of culture were tried with invariably the same result, 

 and as the invariable presence of- an intruding plant of Phteosporese is 

 improbable in the extreme, it is evident that the germinating plant 

 results from the Saccorhiza zoospore. Two sorts of germination arise 

 from the zoospores of the same sporangium. In the author's preceding 

 note he discussed and described the female gametophyte. Here he 

 describes and figures the male gametophyte. Tlie antheridia arise as 

 buds, round and colourless, on cells well coloured with chromatophores ; 

 the apex becomes pointed in the foi-m of a short beak, or the swollen 

 membrane forms a cork ; they measure 7 yx-i) /a by 4 /x.-5 ju., and contain 

 a single antherozoid. A pale red-orange point has often been noticed, 

 but its presence is not constant. In certain preparations motile elements, 

 uncoloured, provided with two lateral cilia have been seen, resembling 

 the antherozoids of certain species of Gystoseira, and which could only 

 belong to Saccorhiza. The element produced by the antheridia is 

 evidently fertilizing ; the female element is furnished by the embryo- 

 spores which increase in size, and the oosphere is the protoplasmic mass 

 which escapes from it. Tiie plantlet is'then the result of fertihzation. 

 Thus it is seen that Saccorhiza and probably all the Laminariaj possess 

 a heterogamic sexuality with alternations of generations. The number 

 of the chromosomes has not been observed. The phenomenon differs 

 so. much from that known among the Phasosporefe, that the Laminariacese 

 must constitute a group of the Brown alga^ of the same systematic 

 importance as Fucaceae and Dictyotaceae. 



Size of Kelps on the Pacific Coast of North America.* — 

 T. C. Frye, (K B. Ptigg, and W. C. Crandall have published the result 

 of their investigations on the size of the kelps, made during many years. 

 They do not confirm the statements of writers on the great length of 

 3facroci/sfis and Nereocystis. The longest plant of Macrocystis found 

 on the Calif ornian coast reached 40 • 7 m., and the longest plant of 

 Nereocyatis reached 38 • 4 m. Pelayophycus forra has been found 45 m. 

 in length on the Californian coast. The observations of the authors on 

 Alar ia fistula sa confirm earlier statements of its length. Its maximum 

 width was found lo be more than twice as great as reported in literature, 

 the widest plant observed being 75 c.cm. 



Marine Algse of the Danish West Indies.t — F, Boergesen publishes 

 the first instalment of his second volume of the Marine Algfe of the 

 West Indies. It consists of part of his treatment of the Rhodophyceie, 

 and contains also Introductions and Indices to the previously published 

 Chlorophyceae and Ph^eophyceje. Many new species are described and 

 all the records are discussed at length and figured. Twenty-one species 

 are described for Acrochselium, each of them being treated with mono- 

 graphic detail. The genus Nemalion is completed and Liagora is begun 

 in the present part. 



* Bot. Gaz., Ix. (1915) pp. 473-82 (figs.). 



t Marine Algse of the Danish West Indies, ii. (1915) pp. 1-80. Copenhagen : 

 B. Luno. 



