The Botany of Iceland - 01.12.1928, Qupperneq 54

378
JOHS. BOYE PETERSEN
Ceratoneis Ehrb.
Ceratoneis Arcus Kutz. V. Heurck, Traité, p. 306, Pl. 10, fig. 401.
E. Icel. 25 - S. Icel. L. 386.
According to the literature this species should occur especially in
running water, and notably in mountain streams. The two habitats I
give from Iceland are likewise places where there is running water, at
any rate at certain times of the year. The species being found by
0strup in 126 samples from Iceland, we must conclude that it is no
aérial alga, but that it may still survive some time after the stream in
which it occurred has dried up.
V. Achnantheæ.
Coeconeis (Ehrb.) Cl.
Cocconeis placentula Ehrb. Cl. Synops. II, p. 169. V. Heurck Syn.
Pl. XXX, íig. 26, 27.
N. Icel. 169.
The species occurs habitually in fresh water, also in Iceland (0strup
126 samples). Hustedt, however, found it in a mountain cave. It is
hardly an aérial species.
Microneis Cl.
Achnanthes delicatula Kutz. Cl. Syn. II p. 190. V. H. Syn. Pl. 27,
fig. 3, 4.
N. Icel. 252 — Vestmannaeyjar L. 399.
Area: Eur., Afr., As., Greenl.
Brackish water species. Found on Testmannaey in a mountain cave
at a height of 20 m together with true fresh water species and other
brackish water species, likewise in Húsavík, among Prasiola crispa and
fresh water and terrestrial forms. It is hardly any true aérial alga, but
may be expected to occur among such in coastal regions.
Achnanthes linearis W. Sm. CI. Syn. II, p. 188. V. Heurck, Syn.
Pl. 27, fig. 31, 32.
N. Icel. 140.
Found in a ditch by the roadside among desiccated algæ. (»Forma-
tion passagére«).
Achnanthes microcephala (Kútz.) Grun. Cl. Syn. II, p. 188. V. H.
Syn. Pl. 27, fig. 20—23.
E. Icel. L. 25 - S. Icel. L. 386.
Area: Eur.
The species was found by Hustedt on irrigated mosses in Silesia,
and about its occurrence in Germany v. Schönfeldt states that it is