The Botany of Iceland - 01.12.1928, Side 97

THE AERIAL ALGÆ OF ICELAND
421
Bumilleria exilis Iílebs. Klebs 1896, p. 389, Taf. II, flg. 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 first found by Klebs in a culture inoculated
with clayey soil containing Botrydium 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 must, in fact,
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. Consequently it has been overlooked or
perhaps taken for a Stichococcus. One of the samples in which I found
it was derived from the »Sæluhús« (a shelter for travellers) on the desolate
Mosfellsheiði. 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 /u thick, 6,6 fi
iong, and in contrast to Stichococcus several chromatophores could be
plainly distinguished in each cell. Further I found it very well developed
in a small lava cave at Skjálvandilljót where sheep took shelter in bad
weather. Here, too, it grew in company with a number 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 sheltered in bad weather,
I have also seen this species in cultures of 7 samples of soil brought
home from Iceland in 1925 by Mr. Molholm-Hansen. 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. Tlie 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 hand, states (Siisswasserflora, Heft 11,
p. 46) that fat and oils are often present in abundance. 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 Hormidium flaccidum (1917, 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