67 



Erythrotrichia Areschoug. 



Pliyeeae Scandinavicae marinae 1850 p. '209. 



1 . Erytlirotricliia cariiea (Dilhv.) J. Ag. 



J. Agardli (liS83) p. 15. 



Conferva carnea Dillwj'ii, Brit. Conf. 18(19 pi. 84. 



Coiiferi'ii ceramicola Lyngb. Hj'dr. 1819 p. 144 tab. 48 D (teste specim.) 



Banj/ia ceramicola Chauvin. Hech. sur I'oi-g. de plii.s. genr. d'Algues, Caen 1842, p. .'i.'J ; Harvey, Pbyc. 



Brit. pi. 317: Hauck, Meeresalg. p. 22. 

 Erythrotrichia ceranticolu .\rescli. I.e. p. 210; Le Jolis (Tluiret) , Alg. mar. Cherb. p. 1U;{ pi. Ill lig. 1— 2!; 



Berthold (1882). 



This species is allached lo Ihe substralum nul by means of a basal layer of 

 cells, but only by the basal cell which gives olf short ramified rhizines radiating 

 in all directions on the surface of the substratum, while the other cells of the fila- 

 ment produce no rhizines. In fig. 8 C the rhizines are rather irregular as the plant 

 was attached to the border of a Porphyra thallus. At the base the filaments are a 

 little thinner than higher u}), but the outer cell-wall becomes by and by incrassaled. 

 The hlaments often attain only a length of 0,5 cm., but where the plant thrives 

 well it becomes at least 3 cm. long. The thickness of the filaments is 1() — 24 p., 

 a little less at the base. 



The cells contain a star-shaped chromatophore with numerous narrow branches 

 radiating in all directions, in particular downwards and upwards, and with a cen- 

 tral pyrenoid. The nucleus is small and not always visible as it is often hidden 

 behind the chromatophore or between its branches (fig. 8 D — F). The vegetative 

 cells contain in general no starch; some specimens collected in Sallingsund, Lim- 

 fjord, in Jul}^ were however the exception in this respect, all cells containing nu- 

 merous small starch grains staining blue-violet with iodine; yet the sterile cells 

 showed not so many starch grains as the sporangia. The length of the cells in 

 proportion to the breadth is rather variable. In specimens collected in January 

 the cells were very short and their contents very dense; their length was always 

 shorter than the breadth, often only a third, while in summer filaments are often 

 met with, the cells of which are 3 — i times as long as broad and then with rather 

 poor contents. Plants collected on Herthas Flak (Kn) in 19 meters depth in Sep- 

 tember consisted of cells of about equal height and breadth. 1 have only seldom 

 met with a few cells divided by longitudinal walls and they gave one rather the 

 impression of being somewhat abnormal. Bkhthold (1. c. p. 25) also found longitu- 

 dinal divisions very seldom, while J. Agardh (I.e. p. 14 — 15) thought that they 

 were common in this species'. 



This species has only non-sexual reproduction. The spore-mother cell is, as 

 well known, cut ofT by an oblique wall at the upper end of a cell which is not 

 dilTerent in form from the vegetative cells. Its formation begins with the nucleus 



' !t tuay be doubtful, vvhetiier all that is referred to thi.s sjiecies by Ibis author, l)elo}igs really 

 to it, as for iust. his Tab. 1 lig. 8, vvluch represeuls a iioh'siphonous pi-oliferous lihiinent. 



9' 



