The Botany of Iceland - 01.12.1942, Blaðsíða 86

312
M. P. CHRISTIANSEN
81. Taraxacum cyclocentrum M.P.Chr. n. sp.
Spec. orig.: Iceland, Húsadalur in Þórsmörk, 8.VII.1937, leg. M. P. Christiansen.
Plate VII, fig. 81. Plate XXXIV, fig. 186.
Planta mediocris—magna, 20—30 cm alta. Folia lutescenti-viridia, purpureo-
maculata, parce in nervo mediano magis araneosa, lingulata—obovato-lanceolata,
integra et grosse dentata, dentibus brevibus, latis, patentibus—sat hamatis vel parum
lobata, lobis 2—4 utrinque latis, brevibus, patentibus, obtusis—breviter acutis, parce
dentatis, lobo terminali magno, lingulato—ovato-rotundato, integro—grosse dentato,
apice rotundato, petiolis brevibus, latissimis, lucide purpureis, nervo mediano pur-
pureo.
Scapi folia superantes, ,+ brunnescentes, sub involucro sat araneosi.
Involucrum basi truncatum. Squamae exteriores laxe patentes—recurvatae, 4—2
X 10—12 mm, ovato-lanceolatae, subtus laete—sat obscure olivaceo-virides, prui-
nosae, anguste albo-marginatae, supra glaucescentes, interiores laete—sat obscure
olivaceo-virides.
Calathium c. 50 mm latum, convexulum, densum—leviter radians, laete luteum.
Ligulae marginales 3.5 X 20 mm, subtus stria cano- vel obscuro-purpurea notatae.
Antherae polliniferae, interiores croceo-purpureae.
Stigmata lutea—leviter obscura.
Achenium dilute stramineum (162), c. 3 mm longum, 0.9—1.0 mm latum,
superne dense, breviter spinulosum, ceterum laeve, in pyramidem 0.7—0.8 mm
longam, subcylindricam abiens. Rostrum 9—10 mm longum.
T. cyclocentrum has yellowish-green leaves, blotched with purple, short, broad
lobes and large terminal lobes with a rounded point; bright heads and finely toothed
fruits. By these characters it is easily distinguishable from the other spotted, purple-
petioled species.
Habitat: Birch-copses, grassy mountain-slopes.
Localities: Húsadalur in Þórsmörk, 8.VII.1937, fr., phot. S.
Geogr. Distr.: Found, outside Iceland, in Greenland. (Igaliko, 1926 (Knud
Jessen), probably introduced from Iceland.
82. Taraxacum dilutisquameum M.P.Chr. n. sp.
Spec. orig.: Iceland, Varmahlíð, 15.VII.1937, leg. M. P. Christiansen. Plate VII,
fig. 82. Plate XXXIV, fig. 187.
Planta mediocris, sat gracilis, 20—25 cm alta. Folia laete—obscure viridia, sat
dense sed breviter araneosa, brunneo- vel purpureo-maculata, maculis interdum (prae-
sertim in foliis juvenilibus) fere ubique confluentibus, obovato-lanceolata—lingulato-
lanceolata, integra, + dentata, margine inter dentes concavo vel parum lobata, lobis
2—4 utrinque, sat distantibus, brevibus, triangularibus, patentibus, breviter acutis,
o—paucodentatis, lobo terminali nunc parvo, triangulari—late ovato-hastato, acutius-
culo, nunc latiore, ovato, marginibus breviter et late dentato, petiolis sat latis—sub-
angustis, lucide roseo-purpureis, nervo mediano purpureo- vel pallido-brunnescenti.
Involucrum basi leviter turbinatum. Squamae exteriores erecto-patentes—-laxe
patentes, 2.5—2.0 mm latae, c. 14 mm longae, lanceolatae-—lineares, subtus dilute
olivaceo-virides, apice paulo rubescenti, supra glaucescentes, interiores laetiores.
Calathium c. 50 mm latum, planum—parce convexum, valde radians, laete
luteum. Ligulae canaliculatae, marginales c. 20 mm longae, c. 2.5 mm latae, apice
planae, subtus stria laete cano-rosea notatae.
Antherae polliniferae, interdum parce polliniferae.
Stigmata luteo-virescentia.
Achenium dilute stramineum (162), c. 2.8 mm longum, c. 1 mm latum, superne