1917 



Hurd; on Algae in Winter 



S4^S 



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 



Desmarestia ligulata herbacea (Turn.) J. Ag. 

 Ectocarpus granulosus (Engl. Bot.) Ag. . . . 



Ectocai-pus siliculosus Kuetz 



Fucus evanescens Ag 



Nereocystis luetkeana (Mert.) P. & R 



Phyllitis fascia (Muel.) Kuetz 



Punctaria latifolia Grev 



Pylaiella littoralis (L.) Kjell 



tW 



t)<! 



H|jKl 



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 granulosus, 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, 

 Callitham7iion, Rhodymenia and Rhodomela. Howe (1914) found only a 

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

 Desmarestia aculeata, 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. 



