Contribution. I. 59 



f. typica. 



Descr. Porphyra laciniata Thur. in Le Jol. Liste Alg. Cherb. p. 100. 



Fig. B „ Harv. Phyc. Brit. t. 92. 



Exsicc. „ ., Arescb. Alg. Scand. exsicc. Nr. 116, 312. 



„ „ var. elongata Aresch 1. c. Nr. 117. 



„ vulgaris Aresch. 1. c. Nr. 261. 



f. umbilicdlis L. (Kleen.) 



Nordl. Alg. p. 23; Ulva umbilicalis L. Spec. PL 2, p. 1163. 

 Descr. Ulva umbilicalis Lyngb. Hydr. Dan. p. 28. 

 Exsicc. Porphyra laciniata f. b. Aresch. Alg. Scand. exsicc. Nr. 260. 



Syn. Ulva umbilicalis Gunn. FL Norv. 2, p. 121. 



„ „ Wg. FL Lapp. p. 506; excl. var. 



This species is also at East-Finmarken much varying, 

 appearing in a rather large number of forms. I have not 

 succeeded in drawing any limits between them, with excep- 

 tion of f. umbilicalis, which is a well differentiated form. 

 The specimens distributed in Areschoug Alg. Scand. 

 exsicc. 1. c. will show some of the forms that I mean by f. 

 typica, or have referred to this form. It varies as to the 

 colour by dried specimens between light flesh-coloured and 

 amethystine. The thickness of the frond is generally 30 — 40 

 pi, but I have collected specimens which were, at the middle, 

 60 p. thick. The difference seems chiefly to be founded upon 

 the conditions at the places where the plant is growing. In 

 the inner part of deep, bays it becomes seldom lobed, but 

 here it often reaches a considerable size. Thus I have seen 

 specimens at Russemark (Porsangerfjord) in West-Finmarken, 

 being in general perfectly simple and attaining a length of 

 2 metre by a breadth of 0.5 m. and more. 



The typical form is litoral or sublitoral. In the former 

 case it grows mostly scattered, attached to rocks or other 

 algse, as Halosaccion ramentaceum, Dumontia filiformis, Mho- 

 dymenia palmata etc. In the latter case I have only met with 

 it fastened to other algse, for inst. Lithothamnia, Ptifofa and 

 Lamimm- It descends to a depth of about 8 fathoms, The 



