388 SUMMARY OF CURRENT RESEARCHES RELATING TO 



bhe middle of October, whatever the age of the individual, the thongs of 

 the lamina are short and much truncated. Then, either the stipes, 

 bearing what remains, are broken off and thrown up on the shore, or 

 bhe lamina is gradually destroyed right down to the bulb. By the end 

 of the autumn nothing else remains, and by the end of the following 

 .March the bulbs, too, have disappeared and the young plantlets are once 

 more developing. Sori occur also on the bulb, arising at or after the 

 disappearance of the upright portion. They spread over the external 

 surface, the papilla?, the haptera, and sometimes over the interior. 

 They remain until the disappearance of the plant. Thus the reproduc- 

 tion is carried on longer by the bulb than by the lamina. Sori from the 

 stipes and lamina collected in October, and sori collected from bulbs in 

 February and March have produced identical plantlets. The zoospores 

 of Phyllaria reniformis, another annual Laminaria, germinate . more 

 rapidly and more uniformly than those of 8. bulbosa. M'onostromatic 

 and polystromatic plantlets, gathered on the rocks by the Banyuls 

 Laboratory, correspond nearly with those of S. bulbosa from the Gulf of 

 Grascony. 



New Species of Fucus.* — C. Sauvageau describes a new specie-. 

 Fucus dichotomies, found by him at the junction of the oyster beds 

 with the heath at Arcachon. It grows intermingled with F. platycarpus 

 and F. vesiculosus, and is easily distinguished at the time of summer 

 fructification, when the tufts attain a length of 30 cm. The author 

 attributes the fact of its not having been recognized heretofore to the 

 probability that the conditions necessary to its existence are not often 

 realized. The period of fructification is shorter than that of the other 

 three common European species. In spring no plant shows the least 

 trace of fruiting, the fronds are 5-7 mm. wide, flat or twisted, often 

 2n-25 mm. long. Long hairs issue from the cryptostomata. In July 

 the apices are suddenly changed into receptacles, and each individual 

 often possesses several hundreds. But it is not till the early days of 

 August that the reproductive organs are capable of fertilization ; they 

 remain fertile till the end of September or beginning of October. Certain 

 individuals disappear after the summer fructification ; others fruit 

 again, thanks to their adventitious shoots. The individuals, of reduced 

 size, which result from the summer germination, fruit in the autumn, 

 then disappear or are maintained by their adventitious shoots. Indi- 

 viduals which germinate in winter, or late in autumn, grow slowly at 

 first ; they will fruit in the following- summer, either directly or on 

 their adventitious shoots. The receptacles diminish in size and number 

 luring the autumn and winter ; at the same time the relative number 

 of the antheridia becomes less. F. dichotomus -is distinguished from 

 F. platycarpus by its flabellate branching, by the simultaneous and 

 abundant transformation of the apices into receptacles, and by the 

 cylindrical form of the receptacles. The plant, being fixed, is pre- 

 served but not propagated by its adventitious shoots, which enable 

 certaii individuals to live for a whole year, or probably even two years. 

 The author discusses the affinity between F. di-chotomus and F. lutarius, 

 and decides that their connexion, if any, was an ancient one. 



* Comptes Rendu?, clx. (1915) pp. 557-9. 



