The Botany of Iceland - 01.12.1928, Blaðsíða 58

382
JOHS. BOYE PETERSEN
Diploneis ovalis var. oblonqella Nag. Cl. Svn. I, n. 93. V. Heurck
Syn. Pl. 10, fig. 12.
E. Icel. L. 7, 8, 24, L. 25, L. 77, L. 85, 99, L. 128, L. 129 — N. Icel.
135, 140, 215, 217.
It has been shown by Bristol (1920) that this form will withstand
intense desiccation, since it grew after grafting from a sample that had
been dried for 6x/2 weeks. Hustedt (1922, p. 98) mentions tliat it oc-
curs frequently in rock caves. 0strup found it in Iceland in 86 samples
from fresh water. Four of the above-mentioned samples, in which I
found specimens of this form with cell contents, were derived from
rocky walls.
Caloneis Cl.
Fig. 7.
Caloneis
angustivalva
Boye P. n.sp.
(X 1200).
Caloneis angustivalva Bove P. n. sp.
E. Icel. L. 41 — N. Icel. L. 219.
Caloneis valva lineari, apicibus rotundatis, long. 18,3/j,
lat. 3,1 p, striis 23 in 10 fi, radiantibus, apices versus conver-
gentibus. Area apicali angusta, in media parte valvæ in fas-
ciam dilatata. Fig. 7.
Found in two places on damp ground, in one of the
places among Vaucheria, in the other among mosses. A very
characteristic little species, which might perhaps with equal
right have been referred to the genus Pinnularia.
Caloneis fasciata (Lagst.) Cl. emend. Cl. Syn. I, p. 50.
If we take this species in the same extension as Cleve (1. c.) it is
a pronounced specics collectiva embracing various probably quite distinct
forms. This was pointed out already by Iiustedt (1909, p. 437). Whether
these forms should rightly be conceived as separate species or merely
as varieties is not quite clear to me, so for the prescnt I will regard
them as varieties. It is almost impossible to find any information in
the literature as to the occurrence of the individual forms, since the
authors as a rule give no particulars as regards the appearance of the
specimens observed. In the literature tlie species is in the main stated
to belong to fresh water, more rarely it is mentioned that it may oc-
cur e. g. among mosses (v. Schönfeld 1913) or in a rocky cave (Hustedt
1922 I). 0strup found it in 46 samples, while I have it from 20 samples
in all. Hence it must be supposed to be most frequent as an aerial
alga, but evidently it will thrive both in water and on land.
The forms of tliis species found in Iceland may be grouped as
follows:
1. Apices subrostrate.
a. Valve linear.................................... var. lijpica.
b. — slightly constricted in the middle . . — fontinalis (Grun.)
2. Apices rounded.
a. Valve linear................................. var. inconstantissima.
b. — elliptic................................... — elliptica n. var.
c. — lanceolate................................. — fonticola (Grun.)