The Botany of Iceland - 01.12.1942, Page 92
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M. P. CHRISTIANSEN
provisionally referred to that group. It seems to be closely related to T. seleno-
phoreum, but the latter has often hamate lobes and larger fruits.
Habitat: Home-fields, birch-copses.
Localities: Hafnarfjörður, l.VII.1937. S.W.—Akureyri, 29.VII.1937, Nes in
Fnjóskadalur, 23.VII.1937, phot., Vaglaskógur, 31.VII.1935, Laugar at Breiðamýri,
27.VII.1937, fr. N.
Geogr. Distr. : Only found in Iceland.
g. Macrodonta M.P.Chr. n. sect.
(Spectabilia Dahlst. p. p.).
Plantae mediocres—magnae. Folia lutescenti-viridia—saturate viridia, raro sat glau-
co-viridia, interdum praesertim fol. exteriorum + purpureo-maculata, glabra—parce
araneosa; petioli saepe pallidi, nervo mediano pallido—leviter colorato. Squamae
involucri exteriores saepe longae, patentes, saepe valde divergentes vel sat recurvatae,
subtus laete—obscure olivaceo-virides, apice laeves, + purpurascentes, supra albo-
virides. Calathium 50—60 mm latum, laete luteum—luteum; ligulae marginales
subtus stria cana—cano- vel brunneo-purpurea notatae. Antherae polline carentes
vel polliniferae. Achenia mediocra—magna, lata, 3.7—5.0 mm (pyramide inclusa)
longa, superne saepe late, grosse, obtuse pauci-spinulosa; pyramide saepe longa, lata,
subcylindrica—-cylindrica. Rostrum 8—10 mm, raro 12—14 mm longum.
Key.
a. Maculata. Upper surface of leaves + blotched with purple, at any rate on outer
leaves.
b. Anthers without (or with a little) pollen. Leaves bluish-green, lanceolate. Lobes
densely placed, rather narrow, hamate and acute.
89. T. selenolobum M.P.Chr.
bb. Anthers with pollen. Leaves often yellowish-green.
c. Leaves strongly purple-spotted. Stigma yellow.
d. Head 40—50 mm broad, very densely flowered. Leaves obovate-lanceolate.
Lobes hamate. Terminal lobe galeate.
90. T. latifrons M.P.Chr.
dd. Head 50—60 mm broad, + radiating. Leaves lanceolate. Terminal lobe long
sagittate—shortly hastate.
91. T. latihastatum M.P.Chr.
cc. Outer leaves only purple-spotted. Stigma green—blackish-green.
d. Leaves lobed. Terminal lobe short, hastate or rhombic.
92. T. rhomboideum M.P.Chr.
(see also 98. T. leucocephalum M.P.Chr.)
dd. Leaves entire and + dentate. Inner leaves obovate-lanceolate with Iong,
patent subulate teeth.
93. T. hypochoeris Dahlst.
aa. Immaculata. Leaves without purple-blotches on the upper surface.
b. Leaves entire, + coarsely dentate.
c. Leaves broadly lanceolate with coarse, hamate teeth.
d. Fruits large and broad with a very long pyramid, inner-fruits with a large,
coarse tooth on each side.
94. T. latispinulosum M.P.Chr.