The Botany of Iceland - 01.12.1928, Qupperneq 88
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JOHS. BOYE PETERSEN
Cymbella Cistula Hempr. Cl. Syn. I, p. 173. V. H. Syn. Pl. II, íig.13.
E. Icel. 128 — W. Icel. 336.
Conimon fresh water species (Ostrup 100 samples). The specimens
found have prohably not lived in the places where they were found,
but have been accidentally conveyed there.
Cymbella naviculiformis Auersw. Cl. Syn. I, p. 166. C. anglica A. S.
Atl. Pl. 9, flg. 63.
E. Icel. L. 99, 114.
Found in Iceland by 0strup in 52 saniples from fresh water. It is
thus a pronounced hydrophilous species, but evidently it can live in
rather dry places. The sample in which I found it in the living state
was from a rock cleft with trickling water where it grew among Nostoc
commune. The other sample was from soil near a farm (Prasiola).
Cymbella gracilis Rabh. Cl. Syn. I, p. 169. V. H. Syn. Pl. III,
íigs. 21-23.
E. Icel. 123 — N. Icel. 161 — S. Icel. 295.
Found by 0strup in 79 samples from fresh water. It must there-
fore be assumed to be a pronounced hydrophilous species.
Cymbella ventricosa Kútz. Cl. Syn. I, p. 168. V. H. Syn. Pl. III,
flg. 16.
E. Icel. 113, 114, 124 - N. Icel. L.? 135, 140, L. 169, 217.
This very common species has a world-wide distribution in fresh
water. 0strup found it in Iceland in 247 samples. Hence it must be
taken for granted that the few and small specimens I found in the
above-mentioned samples have hardly lived in these places. Specimens
with endochrome were only found in one sample (No. 169). This sample
originates from the shore of a lake where the ground was very damp.
The species is thus beyond doubt a pronounced hydrophilous species.
Amphora Ehrb.
Amphora veneta Kfltz. Cl. Syn. II, p. 118. A. quadricostata. A. S.
Atl. Tab. 26, flg. 78-80.
E. Icel. 7.
Brackish water species which, however, has occasionally been found
in fresh water, thus by 0strup, in 4 samples from Iceland. The spe-
cimens found in the sample were very small, one of them had the
following dimensions: L. 15,4/j, br. 6,6 /u, str. abt. 23 in 10 ju.