The Botany of Iceland - 01.12.1942, Page 52

278
M. P. CHRISTIANSEN
sagittato, mucronato, integro vel singulariter et late dentato,, lobulis basalibus +
reflexis, acutis. Folia interiora subintegra, + robuste dentata, dentibus + hamatis.
Scapi folia superantes, pallidi, fere glabri.
Involucrum basi truncatum. Squamae exteriores adpressae—laxe patentes, breves
et latae, ovatae, 3—4 X 8—9 mm, subtus obscure olivaceo-virides, albo-marginatae,
supra glaucescentes, + laete purpurascentes, interiores angustae, c. 20 mm longae,
obscure olivaceo-virides.
Calathium c. 30 mm latum, obscure luteum—obscure croceum, fere densum,
convexum. Ligulae marginales longae, c. 3 mm latae, subtus stria fusco-grisea notatae,
dentibus croceis.
Antherae valde polliniferae.
Stigmata luteo-virescentia.
Achenium immaturum laete stramineum, c. 3.9 mm longum, c. 1.1 mm latum,
superne breviter erecto-spinulosum, ceterum laeve, in pyramidem conicam, c. 0.3 mm
longam, basi parce spinulosam sensim abiens. Rostrum 9—10 mm longum.
T. luteodens is a large, sturdy herb, in the shape of its leaves it is somewhat
reminiscent of big individuals of T. macromerum. The two species, however, may
easily be distinguished from each other. The leaves of the former are yellowish-green
and its head very dark, almost dense and with orange-yellow teeth on all the corollas ;
the latter, on the other hand, has dark-green leaves, the head is large, of a dark-
yellow colour, radiating and with purplish black teeth on the marginal ligulae.
It is spontaneous.
Habitat: Birch-copses.
Localities : Þrastarlundur, 11.VII. 1937, fr., phot. S.W.
Geogr. Distr.: Only found in Iceland.
35. Taraxacum planifrons M.P.Chr. n. sp.
Spec. orig.: Iceland, Varmahlíð, 18.VII.1937, leg. M. P. Christiansen. Plate III,
fig. 35. Plate XXII, fig. 152.
Planta 15—25 cm alta. Folia lucide lutescenti-viridia, brunnescentia, interdum
pauco purpureo-maculata, fere glabra, plana, lingulato-lanceolata, sat regulariter
2—4-loba, petiolis sat latis—angustis, pallidis—paulo coloratis, nervo mediano subtus
pallido, supra + rubescenti, fol. interiorum magis colorato, lobis latis, patentibus—
parce hamatis, acutissimis, antice integris— + dentatis, interlobiis latis, saepe
integris, lobo terminali mediocri—longissimo, sagittato—hastato, + contracto, supra
lobulos basales parce, late et robuste dentato.
Involucrum 12 X 18 mm, basi turbinatum. Squamae exteriores laxe erecto-
recurvatae, 3—2 X 11—13 mm, lineari-lanceolatae—lineares, subtus laete—obscure
olivaceo-virides, claro- vel albido-marginatae, supra glaucescentes, + purpurascentes,
interiores apice purpureo-marginatae.
Calathium c. 45 mm latum, planum, leviter radians. Ligulae obscure luteae,
marginales c. 3 X 17 mm, subtus stria cano- vel roseo-purpurea notatae.
Antherae polliniferae.
Stigmata lutea.
Achenium sat fusco-stramineum (162—153), c. 3.7 mm longum, c. 1.2 mm
latum, superne crebre et minute spinulosum, ceterum + laeve, in pyramidem conicam
—subcylindricam, 0.4—0.6 mm longam abiens. Rostrum 8—9 mm longum.
T. þlanifrons was cultivated and had beautiful, plane, glossy yellowish-green,
almost smooth, regularly lobed leaves and dark heads with narrow, broadly white-
margined outer bracts. Seems to be nearly allied. T. pravicentrum (see the latter).
Surely spontaneous.
Habitat: Grassy spots on rock-ledges, grassy and wet mountain-slopes.