1917 Hurd; on Algae in Winter 347 



Regeneration seems to be a more common phenomenon in winter than 

 in smnmer, judging from the common occurrence of young fronds starting- 

 out from the surface of the old frond in several species. This was true 

 of Nitophyllum riiprechtianum, Gigartina mamillosa, Gigartina radula, 

 Prionitis lyallii, and Fucus evanescens. These young branches were very 

 often in clumps on the flat surface of the old blade, evidently where the 

 plant had been wounded. 



SUMMARY 



1. The winter flora of Puget Sound is not markedly different from its 

 summer flora. The few changes with the arrival of spring are for the 

 most part the appearance of young plants of the summer forms. 



2. A number of algae reported from the Atlantic coast as summer 

 forms only, are present in Puget Sound all winter. 



3. The algae with a conspicuous seasonal periodicity, as shown by 

 the appearance of plants in spring which were not present in winter, are 

 Nereocystis luetkeana, Castaria costata, Laminaria hullata, Laminaria sac- 

 charina, Soranthera ulvoidea, Desmarestia aculeata, Scytosiphon lomenta- 

 I ms, and Odonthalia floccosa. 



4. Young plants of certain species were found more or less commonly 

 all winter but in greatly increased numbers in March, viz., Iridaea lamina- 

 fioides, Prionitis lyallii, Gigartina mamillosa, Fucus evanescens and Ulva 

 lactuca. 



5. While a large number of red algae rej^roduce all winter, a consid- 

 erable number were found only in the vegetative condition. 



6. Fucus plants do not reproduce in winter, the tips, with few ex- 

 ceptions, remaining flat until February. 



7. Although Agardhiella and other red algae are reported from the 

 Atlantic coast as having sexual and asexual generations occurring at dif- 

 ferent seasons, a large number, including Agardhiella and Polysiphonia, 

 were found producing both sexual and asexual spores all winter. 



8. The increase in the relative numbers of carposporic plants of 

 Polysiphonia calif ornica toward the end of the winter, and the young 

 condition of most of the cystocarps found in the winter months, would sug- 

 gest that there is at least a partial seasonal separation of the two gen- 

 erations. 



