— 370 — 



Some specimens have been collected by Lundbeck at Önundarfjöröur in 

 a depth of about 12—14 fathoms, but I doubt that the plants have been 

 growing at that depth. Smaller specimens, more richly furnished with 

 rhizoids, occur in the lower litoral region and form the transition to the 

 next form. 



f. littoralis nov. f. 



The specimens which I have referred to this form are 6 — 14 cm. 

 high. The main branches are about 100// thick below and 200 — 240^ 

 thick above. The sporangia occur singly or two or three in a row; their 

 length is varying and they are sometimes twice as broad as long and in 

 other cases twice as long as broad. The chromatophores of the younge 



Fig. 14. Acrosiphonia hystrix (Strömf.) f. littoralis. 

 a and c show the size of the meshes in younger cells, b in older cells. 



cells is finely reticulated, while the older or longer cells have chromato- 

 phores with large meshes somewhat reminding of A. centralis Kjellm. This 

 form differs from the typical form by narrower branches, more richly 

 occurring rhizoids and more dense growth. Fructiferous specimens have 

 been gathered in April — August. This form in many respects highly 

 resembles A. flaccida Kjellm. (Acrosiphonia p. 65, Tab. Ill, fig. 1—14). My 

 plants occurred for the most part in pools in the litoral region, but some 

 of them have been picked up from a depth of 2 — 3 fathoms. 



A specimen collected by Strömfeit at Seley in E. Icel. in a depth of 

 3 — 5 fathoms and by him referred to Gladophora diffusa seems to belong- 

 to this form, but it differs from my specimens by having the upper 

 branches incurved and slightly tapering towards the apex. The thickness 

 of the main branches is about 160 — 210^. Regarding the incurved 



