— 179 - 



very broad segments. With numerous intermediate forms the main form 

 is connected to both the other forms. 



f. genuina Le Jol. Exam., Kjellm. Handbok p. 23. 



The size of the specimens referred to the main form is, without 

 regard to young plants, much varying. The stipe is 6 — 60 cm. long, 

 and the lamina 50 — 200 cm. long. The stipe is usually terete below and 

 somewhat compressed upwards; as a rule it is thickest below, but the 

 greatest thickness is sometimes to be found in the middle or the upper- 

 most part. With exception of young specimens the lamina is usually split 

 into many segments of different breadth. Sometimes 1 have met with 

 plants, the lamina of which was split into few and broad segments above. 

 Such specimens remind one of Laminaria intermedia (Fosl. Lam. p. 81) 

 and are to be regarded as transitional forms to f. cucullata. Specimens 

 with cuneate base, the lamina of which is split nearly to the base into 

 some few and narrow segments, occurring at low-water mark on somewhat 

 exposed coasts, agree fully with the description of f. cuneata Kjellm. (1. c), 

 and are to be regarded as intermediate forms between the main form and 

 f. stenophylla, closer connected to the latter. Specimens, the stipe of 

 which is compressed above and 3 cm. broad remind one of the f. com- 

 planata Kjellm. (1. c), and specimens agreeing with the description of 

 f. ensifolia Le Jol. (Fig. Fosl. Lam. Tab. 5, f. 2) are met with here and 

 there. 



Specimens changing lamina I frequently met with in April at Rey- 

 kjavik ; I have also in June seen some few plants in change of lamina. 

 Plants gathered in June and August had ripe sporangia, but in October 

 at Reykjavik I met with specimens having young sporangia. 



The main form belongs essentially to the Laminaria-zone, but small 

 specimens are to be found in litoral rock-pools. 



f. stenophylla Harv. Phyc. Brit. Tab. 338. Laminaria stenophylla Ström f, 

 Algveg. p. 45; J. Ag. De Lam. p. 18; Kjellm. Handbok p. 24. 



The most typical specimens of the Icelandic plants agreeing fully 

 with Harvey's fig. ]. c, occur at low-water mark on much exposed coasts. 

 At Vestmannaeyjar it was growing gregariously, and the biggest plant, I 

 collected here, had a stipe 1 m. long, a lamina 133 cm. long and 13 cm. 

 broad split into some few, long and narrow segments nearly to the base. 

 The undivided, lover part of the lamina was 5 cm. long. 



As I have seen in nature a complete series of forms, one of which 

 is the above mentioned f. cuneata ; connecting this form with f. genuina, 

 1 have no doubt that f. stenophylla is to be regarded as an extreme form 

 of Laminaria digitata. 



