:U8 JONS. noTK im:ti:usi:n 



Oii Heimacv (Vestmannaeyjar) (404), on some woodwork near 

 tlu' slioie, 1 roiuid a laver of {^reen alga* which proved to he made 

 up of Psendendocloiuuin snhinarinuiu. 



In llie woods, of \vliicli I have visiled lliose at Egilsta('iir (22,23), 

 HallormslaAir (fiOa), Hals (155, 15(i, 157, 15<S, 159), and Nor5tunga 

 (335), Ihe bark on tlie trunks and branches of the birches as a ride 

 proved quite naked and wilhoul visible algal vegetation, occasionally 

 Nvilh a IVw lichens. In the samples which I collecled in piaces 

 Nvhere 1 found something that mighl resemble algæ, none were as 

 a rule foinid; sometiines I found an imi)erfectly developed lichen 

 thailus or some few algal cells impossible lo determine. 



In Denmark all woodwork as well as the bark of Irees is as 

 a rule covered with a dense laver either of algæ or lichens, and I 

 have previously described in more detail (1915, [). 304 f.) where the 

 one and the other sort of these growths are to be found. However, 

 even i Denmark naked woodwork and naked tree trunks are found 

 in certain piaces, particularly in very exposed localities. 



This will perhaps explain the scanty development ol" Ihis algal 

 communily in Iceland. As regards the prevaiiing winds in Ihat 

 country \ve find the following statement in Den islandske Lods 

 (The Icelandic Pilot) for 1927, 5th ed. p. 27 : 



»As a rule the wind in Iceland blows with a moderate to strong 

 breeze and many storms occur, thus at Stykkisholmr storms average 

 50 days annually, and are most fretjuent in the winter when a storm 

 will occur on an average every fifth day, while in summer storms 

 occur abt. every tenth daj' .... Storms in Iceland present special 

 (langers because they often spring up with great suddenness. Thus 

 it is no uncommon occurrence that a storm reaches its fiill force 

 in less than an hour, but on the other band the wind may drop 

 again with e(|ual suddenness. The (|uick changes in the force of 

 the wind are not only due to the faet that the centres of the cy- 

 clones pass very dose by Iceland, but many of the storms that 

 appear suddenly are local fjord winds which may in piaces be very 

 violenl. As a rule they are then gusty and foehn-like in character, 

 that is to say, they are accompanied by a comj)aratively high tem- 

 perature and only carry a slight degree of moislure . . . Altogether, 

 in the case of the storms, too, local conditions make their influence 

 felt along the coasts of Iceland . 



It must lurthermore be borne in mind llial, since tliere are 

 practically no trees in the island, the wind will be able to sweep 



