757 



Florideæ. It is the haptera and especially llie stalk which are almost 

 densely covered by large or small algæ (see fig. 161). The lamina 

 however is mostly destitute of epiphytes, most likely because it is 

 changed every year. Various species, however, e. g. Rhodymenia 

 palmata, Edocarpus tomentosoides, which would probably be very 

 common in spring, E. tomentosiis , E. fascicnlatiis, and some others, 

 may be found growing on the lamina, especially in shallow water. 



Among the many epiphytes that grow on the stalk and the 

 roots, the following species may be pointed out: Pohjsiphonia iir- 

 ceolata, Chantransia Daviesii, CaUophyllis lacininta, Eiithora cristata, 

 Rhodophyllis dichotoma, Lomentaria claoellosa, L. rosea, Plocamiiim 

 coccineiim, Delesseria alata , D. siiuwsa, D. sangiiinea, Polysiphonin 

 elongata, Odonthalia dentala, Ptilola pliimosa, Pt. pectinata, Antitham- 

 nion floccosum, Ceramiiim rubnim, Rhodochorton Rothii, Criwria pel- 

 lita, Lithophylhim Crouani, Dermatolithon macrocarpiiin f. Laniinariæ, 

 Peyssonelia Diibyi, Splmcelaria fiircigera, Desmarestin aciileatn, D. vi- 

 ridis; that is to say, scarcely any but Florideæ. Most of these epi- 

 phytes may be found even in rather shallow water in the semi- 

 darkness under the Laniinariæ which also afford some protection 

 from the violence of the waves. 



In describing the algæ-vegetation of the Mediterranean Sea, Ber- 

 thold points out (5, p. 422) that the epiphytes on a Cystosira granii- 

 lata grow in a cerlain fixed order. Those that require more light 

 grow on the top of the Cystosira, those that want less grow under 

 the latter. The epiphytes on the stalks of the Laminaria hyperborea 

 likewise grow in a certain fixed order from the top downward, 

 according to the degree of light required by each alga; those that 

 want much light grow uppermost, the others lower down. The 

 colour of the w^ater can hardly be of any consequence where the 

 distance from the top to the bottom oraly means the Icnglh of the 

 stipes. At the top of the stipes we find Ceramiiim riibrum, Pohj- 

 siphonia iirceolata, Delesseria alata, Polysiphonia elongata, and from 

 these algæ downward, we find Odonthalia dentata, Delesseria simiosa, 

 Plocamiiim coccineiim, Ptilota plumosa, Lomentaria clavellosa, Splmce- 

 laria fiircigera, Rhodochorton Rothii, Criwria pellita, Dermatolithon 

 macrocarpiim f. Laniinariæ etc. On the lowest part of the stipes, 

 and especially on the haptera, CaUophyllis laciniata, Rhodophyllis di- 

 chotoma and Eiithora cristata are found. 



The Laminaria hyperhorea-assoc'ial'ion reaches its finest develop- 

 ment in the course of the summer. The lamina is changed in winter, 



