THE AÉRIAL ALGÆ OF ICELAND 421 



Bumillepia exilis Klebs. Klebs 1896, p. 389, Taf. II, fig. 15—20. 

 N. Icel. 179 - S. Icel. 352. 



As far as I know the present species has hitherto only been known 

 from cultures. It was flrst found by Klebs in a culture inoculaled 

 with clayey soil containing Botnjdinm spores. Later Miss Bristol (1920, 

 p. 48, 78) found it in 40 out of 44 samples of English soils inoculated 

 in a nutrient solution. I myself have found it in numerous similar cul- 

 tures of samples of soil from Iceland. From the data it nuisl, in faet, 

 be supposed that it has a very wide distribution on the surface of the 

 globe, but that it rarely occurs there in such large growths that it be- 

 comes macroscopically visible. Consecjuentlj^ it has been overlooked or 

 perhaps taken for a Stichococcus. One of the samples in which I found 

 it was derived from the »Sæluhiis« (a shelter for travellers) on the desolate 

 MosfellsheitM. At the base of the wall was found a green layer consisting 

 chiefly of Prasiola crispa, more sparingly intermixed with diatoms and 

 algæ, amongst others Bumilleria exilis. The cells were 4,5// thick, 0,6// 

 long, and in contrast to Stichococcus several chromatophores could be 

 plainh' distinguished in each cell. Further I found it very well developed 

 in a small lava cave at Skjålvandifljot where sheep took shelter in bad 

 weather. Here, too, it grew in company with a nuniber of diatoms and 

 green algæ. 



Miss Bristol's investigations (1. c.) show that this species will sur- 

 vive a long period of desiccation (as much as 26 weeks\ and it is hardly 

 improbable that it would be able to grow on a wall in company with 

 Prasiola. 



Bumilleriopsis brevis (Gern.) Printz. Printz 1914, p. 50, Tab. IV, 

 fig. 102—108. Ophiocytium breve Gerneck 1907, p.241. Tab. XI. fig. 24-30. 

 Fig. nostra 32, 33. 



N. Icel. 179. 



Besides in the above-mentioned sample originating from the ground 

 in a small lava cave where sheep evidently sheltcred in bad weather, 

 I have also seen this species in cultures of 7 samples of soil brought 

 home from Iceland in 1925 by Mr. Mølholm- Hanse n. I intend to 

 publish a paper dealing with these cultures later on, but I seize the 

 present opportunity to submit a few remarks regarding this evidently 

 rarely observed species. The descriptions of the species disagree in 

 various ways. Printz (1. c.) as well as Gerneck (1. c.) plainly state 

 that neither fat nor starch are found, whereas tannin could be demon- 

 strated. Pascher, on the other band. states Siisswasserfiora, Heft 11, 

 p. 46 that fat and oils are often present in abundancc. This must pre- 

 sumably be due to a mistake. Clear fat-like drops are often seen in 

 the cells, but they do not show the usual fat reactions. More probably 

 we have here the same substance which is mentioned by Piercy as 

 occurring in Honnidiiim /laccidum J917, p. 525 f.). Gerneck mentions 

 that a slight constriction is found at one end of the cell, whereas Printz 

 expressly states that the cells are never capitate and this statement agrees 

 well with his figures. Except in the large involution forms (,Fig. 32 b 



The Botany of Iceland. Vol. II. 28 



