829 



and D. siniiosa, Callithamnion orbnscnht, Fiircellaria fastigiata and 

 many otliers. In the course of winter, especially towards its end, 

 and during the first months of spring, the new lamina appears in 

 the periodically lamina-changing species of Laminariaceæ, e. g. La- 

 minaria digitata, L. hyperborea and L. saccharina, and the old laminæ 

 are Ihrown olT during the months of spring, at which time huge 

 masses of tlie latter are washed ashore on the beach. 



As the vegetative period for several species is much prolonged in 

 Greenland, the same may be said though to a less extent of several 

 species on the Færoese coasts, compared with what is the case on 

 our Danish coasts. Besides the above-mentioned annual algæ, which 

 live somewhat longer, as just stated, we may find, e. g. Desmarestia 

 aciileata with new shoots and densely covered with assimilating hairs 

 as late as June and July, whilst in Denmark it is often hairless al- 

 ready at this time of the year. Rhodomela lycopodioides likewise grows 

 for the greater part of summer on the Færoese coasts, whilst Rhodo- 

 mela siibfiisca, which is closely related to the latter, stops developing 

 at the beginning of the summer on the Danish coasts. On the whole, 

 several algæ which at a certain moment stop developing in our seas, 

 seem to be able to throw out shoots much later in the year on the 

 Færoese coasts; but whether their vegetative period is really pro- 

 longed or whether it is due to the faet, that this period begins later 

 and thus likewise ends later than on the Danish coasts, I cannot 

 say as yet. Tlie latter seems at any rate rather probable. 



As to the time of fructification , it sets in at very different pe- 

 riods of the year for the different species; in my paper on the Ma- 

 rine Algæ of the Færoes I have stated the time of fructification of 

 each species, so far as it is known. As a general rule it may be 

 stated, that the greater part of the Færoese algæ seem to fructify 

 during the summer season. 



Some species, however, have only been found with reproductive 

 organs at other times of tlie year; e. g. Delesseria sangiiinea, found 

 with cystocarps and tetraspores during the last months of the year; 

 Halidrys siliquosa which is sterile in summer, but which had young 

 receptacles in October; Furcellaria fastigiata of which I have seen 

 specimens witli tetraspores in great quantities in November-Decem- 

 ber, whilst specimens with antheridia or cystocarps did not occur 

 in the material, as they are most probably developed during tlie 

 winter montlis, as on our own coasts. 



Some species begin to develop their organs of fructification in 



53* 



