The Botany of Iceland - 01.12.1928, Side 51

THE AERIAL ALGÆ OF ICELAND
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Synedra Ehrb.
Synedra Acus Kutz. Meister 1912 p. 73, Taf. VI, flg. 23.
E. Icel. 129.
Occurred in the sainple in a short form. It is hardly an aerial
species, even though Ostrup lias onl}7 found it in 3 samples from
fresh water.
Synedra ulna Ehrb. var. danica (Kiitz.) Grun. Meister 1912, p. 72,
Taf. VII, fig. 3.
E. Icel. L. 85.
Like tlie preceding form, it is no aerial species. Ostrup lias it
from 148 samples from fresh water.
IV. Eunotieæ.
Eunotia Ehrb.
Eunotia diodon Ehrb. Mayer 1918, p. 104, Taf. I, fig. 47—51.
E. Icel. L. 128.
In a preparation in water from the above-mentioned sample I found
a couple of specimens of this species with cell conlents, whereas I did
not find the species in the corresponding stjTrax preparation. In the
sample, which originated from cracks in a basalt wall, the Diatoms were
found among mosses.
Eunotia exigua (Bréb.) Rabenh. emend. v. genuina A. Mayer. A. Mayer
1918 p. 113, Taf. II, figs. 16, 17.
E. Icel.. 4, 123.
This species is especially distinguished from E. paladosa by being
still slenderer, and by the ends being strongly recnrved. I have found
the following dimensions: L. 14—17,6 p, Br. 2,2—2,3 /u, Str. 20—23 in 10 p.
Found in mýri at a height of 300 m and among mosses on the
ground, in both places together with E. paludosa. Stated by 0strup to
have been found by him in 1 sample. I also found this species in
several of the cultures from Molholm-Hansen’s samples of earth,
together with E. paludosa.
Eunotia gracilis (Ehrb.) Rabenh. A. Mayer, Die bayer. Eun. 1918,
p. 110, Taf. II, ílg. 15. V. Heurck, Traité p. 300, Pl. 9, íig. 368.
E. Icel. 24, 99, 125, 128, 129 - W. Icel. 321.
Owing to the form of the cell, this species can as a rule only be
seen in zone-view. Hence a certain determination of it is difficult or
impossible. Only in sample 321 did I succeed in seeing it from the
valve face. According to the literature it has often been found on moun-
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