The Botany of Iceland - 01.12.1942, Page 23

THE TARAXACUM-FLORA OF ICELAND
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The three Erythrosperma-species are T. arrigens M.P.Chr. (new),
T. brachycranum Dahlst. and T. diversiflorum M.P.Chr. (new). The
latter is a rather good Erythrosperma-species; it is a slender herb and
has rather small violet-red fruits; in the type of leaf it may recall
T. laetum Dahlst., but is hardly closely related to that species. It is fre-
quent in the south on grassy mountain-slopes, and it is no doubt spon-
taneous. T. arrigens has only been found in one place in E. Iceland;
it seems to be a good Erythrosperma-species. T. brachycranum is a
fulvum-íorm, with dark brown fruits and a vigorous growth, forming
a transition to the group Vulgaria. It is frequent in home-fields in
several places in North Iceland and in addition by roads and streets in
the town of Akureyri itself; the species has no doubt been introduced.
The species T. nematolobum M.P.Chr., referred to the group Cera-
tophora, is new and very characteristic. In the characters of the head
it is almost like the above-mentioned T. brachycranum, and the leaves
are often very much lobed with long, almost thread-like, but toothed
lobes; larger leaves may bear a surprising resemblance to types of leaves
of the roadside-forms of T. brachycranum, but T. nematolobum has
big straw-coloured fruits and must be placed in the group Ceratophora,
the species of which, T. norvegicum Dahlst., and to less extent, T. groen-
landicum Dahlst., have finely lobed leaves. It is tempting, however, to
surmise that T. nematolobum is a variety, a gigas-form of T. brachy-
cranum. The chromesome-number of the two species will be discussed
later on.
The Icelandic Fu/íwia-species are:
T. angustisquameum Dahlst. T. sublaeticolor Dahlst.
„ duplidens Lindb. fil. „ tenebricans Dahlst.
„ myvatnense M.P.Chr. n. sp.
The four species already described have, as previously mentioned,
been introduced. T. myvatnense (new), which seems to be closely
related to T. triangulare Lindb. fil. may also have been introduced,
judging from its habitat, in home-fields by Mývatn and near Breiða-
mýri.
The great majority of the Icelandic Taraxacum-species can be
placed in the group Spectabilia Dahlst. This, however, is a heterogeneous
group, containing species of a very different aspect; quite slender
croceum-forms with narrow, thin, smooth leaves, short, appressed
outer bracts, and slightly toothed fruit with a short, conic pyramid (see
plate II and III) are very different from big, sturdy naevosum-forms