The Botany of Iceland - 01.12.1912, Page 163

MARINE ALGAL VEGETATION
149
luxuriant on this species than on the remaining Laminariaceœ. It
happens rather frequently, however, that a rich epiphvtic vegetation
occurs on L. digitata, L. saccharina, Alaria esculenta and Saccorrhiza
clermatodea. The epipliytes generally occur most abundantly on the
older individuals. The vegetation on the stems is usually composed
of species which may be found growing among the Laminariœ,
and tlien belong to the second layer of the under-vegetation, which
can thus be raised upon the Laminaria stems; consequently, it is
very natural that the composition of the species of the epiphytic
vegetation should vary according to the depth. The following
distinction is evident: that the semi-littoral species which grow
epiphytically in shallow water vanish as the depth increases; while,
on the other hand, some of the deep-water species may occur at a
relatively lesser depth.
The following species have been found to occur on stems of
Laminariaceœ, ■ and may almost all be found on Laminaria hgper-
borea: —-
Ahnfeltia plicata. Rhododermis parasitica.
Antithamnion floccosum. Rhodophyllis dichotoma.
A. Plumula v. boreale. Rhodymenia palmata.
Ceramium rubrum. Desmarestia aculeata.
Delesseria alata. D viridis.
D. sanguinea. Ectocarpus confervoides.
D. sinuosa. E. fasciculatus.
Dermatolithon macrocarpum. E. Hinksiæ.
Euthora cristata. E. penicilliformis.
Gigartina mamillosa. E. siliculosus.
Lithophyllum Crouani. E. tomentosoides.
Lithothamnion circumscriptum. Isthmoplea sphærophora
Lomentaria clavellosa. Laminaria digitata.
L. rosea. L. h^'perborea.
Odonthalia dentata. Leptonema fasciculatum.
Petrocelis Hennedyi. Litosiphon flliformis.
Peyssonellia Rosenvingii. Sphacelaria olivacea.
Plocamium coccineum. S. radicans.
Polysiphonia arctica. Monostroma fuscum.
P. parasitica. M. Grevillei.
P. urceolata. M. undulatum.
Porphyra miniata. Ulothrix tlacca.
Ptilota pectinata. Ulva Lactuca.
P. plumosa. Ulvella fucicola.
Rhodochorton rejiens. Urospora Wormskioldii.
R. Rothii. 51 species in all.
In addition, the fungus Dotliidella Laminariœ must be men-
tioned; it is a very common endophyte in the stipe of various