The Botany of Iceland - 01.12.1928, Síða 52

376
JOHS. BOYE PETERSEN
tain slopes, among mosses, and in a mountain cave (Hustedt 1922 I,
p. 99). I have found it myself in Denmark (1915 p. 295) in similar places.
The species has been found by 0strup in 48 samples from fresh water,
so it may perhaps be inferred that in Iceland the species grows pre-
dominantly in water, though it often occurs as an aérial alga, especially
on damp rocks.
Eunotia lunaris Grun. Van Heurck, Synops. Pl. 35, figs. 3-6a.
S. Icel. 295.
Oniy a single specimen was found in the sample. Probably a fru-
stule which has been carried accidentally to this locality.
Eunotia paludosa Grun. A. Mayer 1918 p. 113, Taf. I, íig. 8, 9. E. lu-
naris var.? Boye Petersen 1924 III, p. 20.
E. Icel. L. 4, 8, L. 123, 124, 129 - N. Icel. 140.
I found this little Eunotia, which I liave previously mentioned as
E. lunaris var.? (loc. cit.), in 5 samples from E. Icel. and 1 from N. Icel.,
partly from mýri and partly among mosses and on vertical rock faces.
It lias the following dimensions: 1.15—26 /z, br. 3,8—3,7str. 20—23
in 10,«. It is slightly curved with parallel dorsal and ventral side, while
the ends are sometimes slightly upward curved. It thus shows a fairly
close correspondence with E. paludosa as described by A. Mayer (1. c.).
It is also very reminiscent of certain forms of E. arcuata Steinecke
(1916, p. 40, fig. 13), but it seems to me that several species may lurk
under this name, none of the forms described agreeing closely with
those observed by me. 0strup mentions the species as occurring in two
samples. This species occurred in a quantity of individuals in not a
few of the samples of earth collected by Molholm-Hansen in the
summer of 1925. It may then be inferred that it is often present on
the ground though it would seem as if it did not belong to the species
that will withstand much desiccation.
Eunotia pectinalis (Dillw.) Rabenh. var. impressa O. Múller. A. Maycr
1918, p. 115, Taf. II, figs. 23—25. E. impressa var. angusta. V. Heurck
Synops. Pl. 35, íig. 1.
E. Icel. 4, 140.
This is hardly any pronouncedly aérial species, though according
to Hustedt (1922, p. 99) it thrives well on irrigated mosses, and so
may be expected to occur, inter alia, on mýri in Iceland. Found by
0strup in 30 samples from fresh water.
Eunotia prærupta Ehrb. f. curta Grun. A. Mayer 1918 p. 103, Taf. I,
íig. 30—34. V. Heurck Synops. Pl. 34, íig. 24.
E. Icel. 24, 28, L. 41, 68, L. 70, 85, 112, L. 123, 129 - N. Icel. 160.
252, 256 — W. Icel. 321, 336 — S. Icel. 295, 327.
E.prœrupla seems in the main to be an alpine-boreal species. As
a matter of i'act, 0strup found it in 82 samples from Iceland. In 15