THE AERIAL ALGÆ OF ICELAND 



405 



f. 2. E. Icel. L. 40, L. 92, L. 121 - N. Iccl. L. 179, L.253 — X. W. Icel. 

 L. 268 — W. Icel. L. 307, 309a, 321 - S. Icel. L. 295, L. 353, 381. 



f. 3. E. Icel. 41, L. 68 — N. Icel. L. 184, 217, 218, 

 L. 241. 



f. 4. Vestmannaeyjar L.399, L.401, L.408. L.409. 



f. 5. Vestmannaeyjar L. 399, L. 400, L. 408. 



f. 6. E. Icel. 69. 



Thus, taken as a wliole, the species has 

 been found in nearly all parts ol' the country 

 and in very diverse localities, in the highlands 

 as well as the lowlands. on mineral ground as 

 well as on ground more or less rich in manure 

 near human habitations, and finally also at the 

 hot springs. Of the individual formæ f. 1 and 

 f. 2 are the commonest, they often occur together 

 and in just as diverse localities as the species 

 as a whole. F. 3 was found partly on damp 

 rock, partly near hot springs; but it is not certain 

 whether these localities are its peculiar habitat. 

 F. 4 and f. 5 were only found on the rocks on 

 the shore of the Vestmannaeyjar, at a considerable 

 height (20— 50m) above the sea, it is true, though 

 not quite beyond its influence perhaps. The rocks 

 were inhabited by numerous sea hirds whose 

 droppings no doubt contributed to produce the special lifc conditions 

 in this place. 



Fig. 24. Pinniihtria intcr- 



media Lgst. 



a. f. 1; 1), c. f. 2; d. f. 3; 



c, f. 4; f, f. 5; g, f. (5. 



(X 1200). 



Pinnularla interrupta W. Sm. f. minor n. f Fig. 25. 

 N. Icel. 215, 218 -W.Icel. 338 - S. Icel. L. 364, L?295. 



L. 22— 30/f, br. 4,8-6/(, str. 14 in 10 /r Valve linear, 

 rostrate-subcapitatc, apical area narrow, transapical fascia 

 present The striæ radiate in the middle, converging 

 strongly at the apices. Approaches P. .s/;/><Y//;;7a/</ from which, 

 however, it differs distinctly by its finer, more radiale, and 

 converging striation. Especially it shows close afdnity to 

 N.Hilscaiui Janisch (A. S. Atl. T. 45, fig. 6o\ which is referred 

 by Cleve Syn. II, p. 75) to P. subca])itata. Stockmayer 

 (1909 p. 85) has likewise found s|)ecimens intermediate 

 between P. internipla and P. siibatpilata. The occurrence of 

 such intermediate forms was already mentioned by Cleve 

 (Syn. II p. 76). 



4 of the above-mentioned samples were collected near hot springs, 

 the 5th (No. 295) on the ^hlai)« by a farm. 



Fig. 25. 



Pinniihtria 



internipla 



W. Sm. 



f. minor n. f. 



(X 1200). 



Pinnularla lata Bréb. var. Rabenhorstii Grun. Cl. Syn. II. p. 81. Grun. 

 1860, p. 515, PI. IV, f. 13. 



E. Icel. 24, L. 68, L. 69, L. 70, L. 129 - S. Icel. 294. 



The Botany of Iceland. Vol. II. 27 



