Ability of Seaweeds to Withstand Desiccation 



Walter L. C. Muenscher, 

 University of Nebraska, Lincoln. 



As one walks along a rocky seashore one cannot help observing the 

 distribution of the seaweeds. Some species grow high up on the rocks 

 almost near the high tide mark, others grow near the low tide, while others 

 grow only where they are constantly submerged. It has been the writers 

 aim to determine approximately how much desiccation some of these 

 algae can stand and to see whether there is any relation between the 

 fibility of seaweeds to withstand desiccation and their distribution above 

 the low tide line. The work was done between June 25 and July 27, 

 1914, under the direction of Dr. T. C. Frye, at the Puget Sound Marine 

 Station at Friday Harbor, Washington. 



For lack of time the work w^as been confined to thirteen species which 

 are named below, under their respective groups. 



1. Chlorophyceae : Ulva lactuca 



2. Phaeophyceae : Alaria valida, Nereocystis luetkeana, Des- 

 marestia aculeata, Fucus evanescens, and Colpomenia sinuosa. 



3. Rhodophyceae : Sarcophyllis calif ornica, Iridaea laminarioidea, 

 Gigartina, Rhodomela larix, Gloiopeltis furcata, Porphyra perforata, and 

 Ilalosaccion glandiforme. 



Arranging the plants in the order of their distribution on the shore- 

 line, beginning with the forms which are highest on the rocks and going 

 toward the low tide line, we get the following order: 



1. Gloiopeltis furcata 8. Iridaea laminarioides 



2. Fucus evanescens 9. Ulva lactuca 



8. Gigartina mamillosa 10. Sarcophyllis calif ornica 



4. Colpomenia sinuosa* 11. Alaria valida 



5. Rhodomela larix** 12. Desmarestia aculeata* 



6. Porphyra perforata IS. Nereocystis luetkeana 



7. Halosaccion glandiforme 



*Colpomenia sinuosa grew on Rhodomela larix, Desmarestia 

 aculeata grew on Nereocystis leutkeana. 



**Rhodomela laryx grew in tide pools. 



Of course the areas occupied by these diflPerent species overlap to 

 some extent so that no definite dividing lines can be drawn. This is par- 



(19) 



