146 



The species occurs in all the Danish waters except the Baltic, growing in the 

 littoral region, thus being out of the water at low-tide. It varies but little in shape 

 in the ditferent localities; it attains very often a lengtli of ca. 20 cm., but larger 

 specimens not seldom occur; thus specimens measuring 40 cm. were met with at 

 Harboore and Gilleleje. It has been found in the months July to November; in 

 the remaining part of the year it is probably represented by the creeping filaments 

 described by Miss Chester which were, as mentioned above, observed by me in 

 February. It may be supposed that the germination takes place immediately after 

 the setting free of the spores but that the erect plants only develop in the next 

 summer. I found however in November on the mole at Gilleleje young plants from 

 less than 1 mm. to a few cms. in length; they would probably have perished during 

 the winter, but possibly the basal portions would have been able to produce new 

 erect fronds. 



The species is said to be as a rule monoecious; I found it however most 

 frequently dioecious in the Danish waters. In the proportionally few monoecious 



specimens (about 10 per cent) I found the two kinds of 

 sexual cells near to each other in all parts of the plant 

 and there is thus no reason to believe that the dioecious 

 specimens would have proved to be really monoecious 

 on closer examination. Antheridia occur in all the months 

 July to November, but in the last months they are in 

 a great measure emptied. Ripe cystocarps may occur 

 already in July; in August a great part of the spores 

 Ncmaiiiin iiniiiifidtim . Antheridiai are oftcu Set free as Well as later, in November how- 



'''""''"'%TamL't"*'.3!S"r""'''"''' ^""'^'^ cystocarps containing most of the spores may still 



be found. 



In aulumn or the beginning of the winter the plants gradually die, the 

 assimilative lilaments being the first destroyed. This may begin already in Au- 

 gust, but on the other hand fairly well-kept specimens are to be found still in 

 November. 



The species prefers agitated water; it therefore grows on the outer, not on 

 the inner sides of the moles. It occurs on stones but also on wood, often together 

 with Fucus. 



Localities. Ns: Groins at Harboere and Thyboran. Sk: Hanstliolm, on a boulder near 

 land; Lonstrup (Warming); Hirshals (!, Bargs.) ; Skiveren, on wreck. — Lf: Oddesund; Struer; Ejerslev 

 Ren. — Kn: Frederikshavn; harbour of Vestera, Ljcsa ; Hornex, Lses0 (J. P. Jacobsen). — Ke: Gilleleje 

 (Lyngb., !). — Km: Anholt harbour; Herringholm (Lyngbye). — Ks: Grenaa harbour; Tisvilde (C. Rasch); 

 near Klintebjerg, Odsherred (J. Vahl); Isefjord: Nykobing; Lynjes ; off Nordskov; Oure; Holb;ek Fjord; 

 Bramsnies y\g. — Sa: Kyholm, in the middlemost Fucus-zone; Sselvig (Hjalmar Jensen) ; Koldby Kaas; 

 Hofmansgave (Hofm. Bg. , Lyngb., C. Rosenb.l; Juelsminde. — Lb: Bogense. — Sf: Radlok Grund off 

 Nakkebolle Fjord; Svendborg; Birkholm; Rudkobing. - St): Kerteminde; Korsar; Lohals. — Sm: 

 Guldborg. — Sli: Hellebtek; Helsingor; Humleb;ek iHenn. Petersen); near Hveen (0rsted); Trekroner 

 near Copenhagen (0rsted). 



