1917 



Hurdj on Algae in Winter 



34y 



Tables 1 and 2 are a list of all algae found growing in a healthy 

 condition in December, 1916, and January and February, 1917, together 

 with a record of their reproduction and the presence of young plants. The 

 observations are not separated by months because the failure to find a 

 certain form in any one month could not always be taken to mean that it 

 was no longer growing. 



Table 2. Winter condition of the Phaeophyceae and Chlorophyceae 





►tjk; 



Desmarestla ligulata herbacea (Turn.) J. Ai 

 Ectocarpus granulosus (Engl. Bot.) Ag. . 



Ectocarpus siliculosus Kuetz 



Fucus evanescens Ag 



Nereocystis luetkeana (Mert.) P. & R 



Phyllitis fascia (Muel.) Kuetz 



Punctaria latlfolia Grev 



Pylalella littoralis (L.) Kjell 



Cladophora arcta (Dill.) Kuetz 



Enteromorpha intestinalis (L.) Link 



Enteromorpha linza (L. ) J. Ag 



Ulva lactuca L 



Of these Puget Sound algae Davis (1911) reports only the following 

 as actually found growing at Woods Hole in winter: Ulva lactuca, Phyl- 

 litis fascia, Ectocarpus gramdosus, and Ectocarpus siliculosus. He found 

 other species of Porphyra, Fucus and Cladophora. He gives as spring or 

 summer forms a considerable number which were found mature in Puget 

 Sound in midwinter, viz., Enteromorpha linza, Polysiphonia urceolata, 

 Cladophora arcta, Desmarestia aculeata, Fucus evanescens, Ceramium stric- 

 tum and Gracilaria confervoides, besides other species of Antithamnion, 

 Callithamnion, Rhodymenia and Rhodomela. Howe (1914) found only a 

 "battered and weather-worn fragment" of Agardhiella tenera, a "denuded" 

 Desmarestia acideata, and among others, specimens of Ceramium rubrum 

 and Polysiphonia urceolata formosa. This leaves a considerable number 

 of the Puget Sound algae which have not yet been reported as winter forms. 



One may classify the algae of table 1 on the basis of their reproduction 

 into the 6 groups below, of which group 5 constitutes those so commonly 

 found that it can be fairly concluded that they do not ordinarily reproduce 

 in winter, group 6 those found so rarely that the absence of reproducing 

 specimens does not mean much. 



