The Botany of Iceland - 01.12.1942, Blaðsíða 123

THE PTERIDOPHYTA AND SPERMATOPHYTA OF ICELAND
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Icelandic: Blöðkunykra. Danish: Svommende Vandaks. English: Floating Pond-
weed, Batter-dock, Flatter-dock, Tench-weed.
Curiously enough this species is not admitted in Gronlund’s Flora, although it
was recorded by König & Miiller and several other earlier authors.
The Icelandic specimens of this plant seem to belong to the var. prolixus Koch,
Syn. ed. 2 (1844), p. 775 (= var. fluviatilis Fries, 1828, non Schlecht.) : Leaves
oblong-lanceolate; further, internodes and petioles stretched.
Here and there in N. and in the southwestern parts, otherwise rare, not in the
central parts, see fig. 35 (some of the records from the literature may be somewhat
doubtful).
Life-form: HH (Hydrophyte).
In smaller lakes, tarns, rivulets.
Flor. VII—VIII; fr. mat. (?).
Max. length: 90 cm; average: about 50 cm.
Geogr. area: Am.: Temperate and subtrop. regions.—Eur.: Fær.; E.S.I.; throughout
Eur.—Asia: Temperate and subtropic regions.
Potamogeton þectinatus Linn.
K. & M., 1770, p. 205/—Babington, 1871, p. 335.-—E. Rostrup, 1887, p. 183.—
Bennet, 1890, p. 81.
This species was recorded by K. & M., loc. cit., and it was included in several
of the older lists; even E. Rostrup, loc. cit., admitted it and records several localities.
(coll. A.F.). The specimens in question are, however, P. filiformis, which have been
wrongly determined. Among these, however, a single specimen from Laugarvatn, S.,
has with some doubt been determined by O. Hagström as P. filiformis X P. pecti-
natus; thus it is possible that P. pectinatus can be found in Iceland. See also under
P. filiformis, p. 119.
40. Potamogeton perfoliatus Linn., Sp. pl. ed. I (1753) p. 126.
Gliemann, 1824, p. 183.—Babington, 1871, p. 335.—Gronlund, Isl. Fl., 1881,
p. 105.—Stefánsson, Fl. ísl., ed. 1, 1901, p. 19.—Ibid., ed. 2, 1924, p. 22.—
C.H.O., Fl. arct., 1902, p. 20.—O. & Gr., 1934, p. 12.
Flora Dan. tab. 196.
Icelandic: Hjartanykra. Danish: Hjertebladet Vandaks. English: Perfoliate Pond-
weed.
Rather frequent in a limited area in the southwestern parts, and in N. at Mý-
vatn; otherwise rare; not recorded from the central regions. See fig. 36.
Very variable in respect of size and form of leaves, as also in the length of the
internodes, the latter measuring from 0.5—12 cm; the length of the peduncles is
from 3—12 cm, average 7 cm.
Life-form: HH (Hydrophyte).
In lakes and slow-running streams.
Flor. VII—VIII; fr. mat. VIII.
Max. length : 82 cm ; average : 40 cm.
Geogr. area: Am.: Nova Scotia to British Columbia, southward to California and
Florida.—Eur.: Fær.; E.S.I.; northern Scandinavia to southern Eur.; Caucasus.—
Northern Asia southward to Himalaya, India, Kamchatka.—Africa: Algeria, Mo-
rocco.—Australia.