The Botany of Iceland - 01.12.1928, Qupperneq 53

THE AERIAL ALGÆ OF ICELAND
377
samples I found small specimens of the species, but in most cases I
could only flnd empty frustules. There is reason to believe, however, that
the species is very widespread and frequent on the ground in Iceland,
even though it hardly helongs to the species that withstand desiccation
well. It occurred commonly in sample 70 from a mountain ravine with
trickling water in Hallormstað Wood, where it grew among Cyanophyceæ.
Eunotia prærupta Ehrb. var. muscicola Boye P.
n. var. (Fig. 3).
Linea ventrali ad apices recta, in medio curvata,
valva long. 26,4 p, lat. 6,8 p, striis 11 in 10in medio,
15 in 10 /i ad apices.
E. Icel. L. 123, 124, 128.
This variety is especially remarkable by the form
of its ventral side, further it is about equally broad
throughout its whole length, so that the dorsal and
ventral sides have the same form. It is besides some-
what finer-striated than the ordinary forms of E. prœ-
rnpta. I have therefore thought it right to describe it
as a special variety.
In all three samples it was found among mosses.
Fig. 3. Eunotia
prœrupta Ehrb.
v. muscicola
Bove P. n. var.
(X 1200)
Eunotia prærupta Ehrb. var. bidens Grun. f. minor. V. Heurck Synops.
Pi. 34, flg. 22. A. Mayer 1918 p. 103.
E. Icel. 77 - N. Icel. 256.
I have onty found this form in two samples, and in these only in
few specimens.
Eunotia robusta Ralfs var. tetraodon Ralfs. A. Maver 1918 p. 105;
V. H. Syn. Pl. 33, flg. 11.
E. Icel. 123 — N. Icel. 256.
Area: Eur.
Only found in few specimens in tlie samples. Not previoush' found
in Iceland.
Eunotia sudetica (O. Miiller) Hustedt emend. A. Maj'er 1918, p. 118,
Taf. II, fig. 52-53,
S. Icel. 295.
Area: Eur.
Only a single specimen observed in thc sample. Not previously
found in Iceland.
Eunotia triodon Ehr. V. Heurck Traité p. 303 Pl. 9, lig. 383.
N. Icel. 256.
Only a few specimens were found in the sample.
aérial species.
It is hardly an