190 KJELLMAN, THE ALG^. OF THE ARCTIC SEA. 



within the Laminariacese-formatioii. Most of the Greenland specimens are collected in 

 March and April, some in October, which seems to indicate that the plant is to be 

 found here all the year round. Judging from these specimens it also bears repro- 

 ductive organs at different seasons. 



Geogr. Distrib. Its maximum of frequency is no doubt in Baflan Bay. Besides, it 

 has been observed in the eastern part of the Greenland Sea. The northernmost locality 

 where it is at present known to grow, is Fairhaven, on the north-west coast of Spitz- 

 bergen, Lat. N. 79° 49'. 



Localities: The Greenland Sea: the north-west coast of Spitzbergen, rare. 



Baffin Bay: Kakertok, Tessarmiut Bay, Kangek (near the same bay), Julianeshaab, 

 Egedesminde, Godthaab. If the P. vulgaris of Croall and Dickie is the present species, 

 as I think it is, D. minatum, is known also from Disco Bay and Whale Sound. 



Gen. Porphyra Ac. 



Syst. Alg. p. XXXII. 



Porphyra laciniata (Lightf.) Ag. 



]. c. p. 190. Ulva laciniata Lightf. Pi. Scot. p. 974. 



f. typica. 



Descr. Porphyra laciniata Thur. in Le Jol. Liste Alg. Cherb. p. 100 — 101. 



Fig. » « Harv. Phyc. Brit. t. 92. 



Exsicc. » " Aeesch. Alg. Scand. exsicc. N:o 116. 



f. umhilicalis (L.) Kleen. 



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

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

 Exsicc. Porphyra laciniata f. b. Aresch. Alg. Scand. exsicc. N;o 260. 

 Syn. Porphyra laciniata Aresch. Phyc. Scand. p. 404. 



M » Gobi, Algenfl. Weiss. Meer. p. 50. 



» « Kleen, Nordl. Alg. p. 23; excl. var. lineari et vulgari. 



» » umbilicata Eupr. Alg. Och. p. 393. 



1) » vulgaris Nyl. et Ssel. Herb. Mus. Fenn. p. 75. 



Ulva umbilicalis Gunn. F1. Norv. 2, p. 121. 

 » » Wg. F1. Lapp. p. 506; excl. var. 



Remark on the species. Thuret has pointed out that what is set down by algo- 

 logical authors under the name of P. linearis, P. vulgaris or P. purpurea, and P. laci- 

 niata, sometimes as separate species, sometimes as forms of the same species, is in fact 

 nothing but one and the same plant at different stages of development; cp. Thue. 1. c. 

 This being so, the names P. linearis, vulgaris, and purpurea, ought to be struck out 

 altogether. The plant described under the name of Ulva umbilicalis or U. umbilicata 

 I think ought to be regarded as a special form of P. laciniata. It differs from the 

 typical P. laciniata both biologically and morphologically, and is well known to Scandi- 



