The Botany of Iceland - 01.12.1942, Blaðsíða 97
THE PTERIDOPHYTA AND SPERMATOPHYTA OF ICELAND
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Icelandic: Eskigras (Eskibróðir, H.J. in mscr.).
This species which, in its morphological and anatomical characters, as also by
its size, occupies a position between E. hyemale and E. variegatum (cp. G. Samuelsson
in Svensk bot. tidskr. V, 1911, p. 928 et seq.) has usually been looked upon as a
hybrid between these two species. The fact that the cones are sterile or semi-sterile
may indicate hybridity, but is no criterion, as sterile or semi-sterile cones occur in
all species of Equisetum under circumstances where recent hybridization may be
looked upon as impossible (cp. G. Samuelsson, l.c., and J. H. Schaffner, American
Fern Journal, vol. 21, 1931, p. 99, et seq.).
Schaffner, l.c., p. 100, gives a description of E. trachyodon, as follows: The
sheaths are cylindrical, mostly all black or with a wide black band at the top. They
are usually very crustaceous and the thicken-
ing does not extend very far into the short,
narrow, mostly persistent teeth. They have a
truncate appearance even when the teeth are
not broken off. This character increases its
resemblance to E. hyemale (cp. fig. 15).
In American Fern Journal, vol. 22, 1932,
p. 72, Schaffner adds the following to the
description already cited : “the sheaths are
cylindric, tight, often crusty, partly or com-
pletely black; stems rather large to medium,
sometimes rather slender”.—Only from two
localities in Iceland have I seen specimens
which could be referred with certainty to E.
trachyodon A.Br. Thus in H.H. are kept
specimens from Góðaland, D. 10 (leg. H.J.,
1911) from Arnarvatnsheiði, W., D. 12
(leg. H.J., 1910). Steindórsson (1937,,p. 4)
records it from Víðidalir in Lón, E. (coll.
1935). I have not seen his specimens. See
fig. 15.
Life-form: H.
On sandy or gravelly soil.
Geogr. area: N. America ?.—Greenl. : W. 60°53'.—Eur.: S.I.; Sweden, Latvia,
Rhineland.
Fig. 15. a. Equisetum hyemale L.
b. E. trachyodon A. Braun. c. E.
variegatum Schleich. a and b 2:1,.
8. Equisetum variegatum Schleich., Cat. Pl. Helvet. ed. 2 (1807)
p. 27.
Babington, 1871, p. 346.—Gronlund, Isl. Fl., 1881, p. 138.—Stefánsson, Fl. Isl.
ed. 1, 1901, p. 11. Ibid. ed. 2, 1924, p. 11,—C.H.O., Fl. arct., 1902, p.
9,—O. & Gr. 1934, p. 3.
Flora Dan. tab. 2490.
Icelandic: Beitieski, Móeski. Danish: Liden Padderokke. English : Variegated Horse-
tail.
Common in all parts, in the lowland as well as in the central highland, up to
1000 m.
The variety anceþs Milde (Bot. Zeitg., 1864, Beilage, p. 14) occurs in Iceland,
and this slender form has been wrongly determined by several botanists as E.