Askellia
Etymology
The genus Askellia was named by Weber (1987) in honour of Áskell Löve (1916-1994), an Icelandic systematic botanist, student of Arne Müntzing and Eric Hultén, one of the founder of the Flora Europaea project, founder and first president of the International Organisation of Plant Biosystematists, with a particular interested in plant chromosome numbers.
Weber W. A. 1984: New names and combinations, principally in the Rocky Mountain flora IV. – Phytologia 55: 1-11.
References
Weber W. A. 1984: New names and combinations, principally in the Rocky Mountain flora IV. – Phytologia 55: 1-11.
Systematics
The treatment of the former Crepis sect. Ixeridopsis (Babcock 1947) as a separate genus Askellia (Weber 1984) has been corroborated by Pak & Bremer (1995) based on a morphological analysis, more recently by Sennikov & Illarionova (2008) based, in particular, on carpological investigations, and by Enke & Gemeinholzer (2008) based on molecular phylogenetic analyses.
While Sennikov & Illarionova (2008) placed Askellia in a new subtribe Ixeridinae together with Crepidiastrum, Ixeris, Ixeridium, Youngia and its three segregates there newly recognised, Enke & Gemeinholzer (2008) found Askellia near to Crepis s.l. in their ITS tree, but in a monophyletic and unresolved group with Ixeris, Youngia and Garhadiolus in their chloroplast phylogeny, their two analyses including, however, only few Crepidinae taxa outside Crepis. The molecular phylogenetic analysis of the Cichorieae based on ITS by Gemeinholzer & al. (in Kilian & al. 2009) showed Askellia as sister group to the clade comprising Crepis, Lapsana and Rhagadiolus on the one branch and to Acanthocephalus, Crepidiastrum, Ixeris, Taraxacum and Youngia on the other. More recently, Zhang & al. (in prep.) revealed Askellia in their molecular phylogenetic analyses of subtribe Crepidinae as part of a well supported clade including Ixeridium, Ixeris and Taraxacum, in there being sister to the subclade including Ixeris and Ixeridium.
Askellia can be fairly well distinguished from Crepis in the typical delicate growth with a basal leaf rosette, the nearly always entire leaves, the few-capitulate synflorescence, the conspicuously slender, narrowly cylindric involucre, the outer phyllaries usually being less than 1/4, rarely to 1/3 as long as inner ones, the usual absence of an indumentum, the smaller number of flowers per head (5-15), the slender achenes with 10 thin, equal ribs and the chromosome number of x = 7.
Askellia comprises 11 species, which are distributed in SW, central and NE Asia and extend with two species into North America.
Babcock E. B. 1947: The genus Crepis. – Univ. Calif. Publ. Bot. 21-22.
Enke N. & Gemeinholzer B. 2008: Babcock revisited: new insights into generic delimitation and character evolution in Crepis L. (Compositae : Cichorieae) from ITS and i>matK sequence data. – Taxon 57: 756-768.
Kilian N., Gemeinholzer B. & Lack H. W. 2009: Tribe Cichorieae. – Pp. 343-383 in: Funk V., Susanna A., Stuessy T. & Bayer R. (ed.), Systematics and evolution of the Compositae. – Vienna: IAPT.
Pak J. H. & Bremer K. 1995: Phylogeny and reclassification of the genus Lapsana (Asteraceae : Lactuceae). – Taxon 44: 13-21.
Sennikov A. N. & Illarionova I. D. 2008 ["2007"]: Generic delimitation of the subtribe Ixeridinae newly segregated from Crepidiinae (Asteraceae-Lactuceae). – Komarovia 5: 57-115
Weber W. A. 1984: New names and combinations, principally in the Rocky Mountain flora IV. – Phytologia 55: 1-11.
While Sennikov & Illarionova (2008) placed Askellia in a new subtribe Ixeridinae together with Crepidiastrum, Ixeris, Ixeridium, Youngia and its three segregates there newly recognised, Enke & Gemeinholzer (2008) found Askellia near to Crepis s.l. in their ITS tree, but in a monophyletic and unresolved group with Ixeris, Youngia and Garhadiolus in their chloroplast phylogeny, their two analyses including, however, only few Crepidinae taxa outside Crepis. The molecular phylogenetic analysis of the Cichorieae based on ITS by Gemeinholzer & al. (in Kilian & al. 2009) showed Askellia as sister group to the clade comprising Crepis, Lapsana and Rhagadiolus on the one branch and to Acanthocephalus, Crepidiastrum, Ixeris, Taraxacum and Youngia on the other. More recently, Zhang & al. (in prep.) revealed Askellia in their molecular phylogenetic analyses of subtribe Crepidinae as part of a well supported clade including Ixeridium, Ixeris and Taraxacum, in there being sister to the subclade including Ixeris and Ixeridium.
Askellia can be fairly well distinguished from Crepis in the typical delicate growth with a basal leaf rosette, the nearly always entire leaves, the few-capitulate synflorescence, the conspicuously slender, narrowly cylindric involucre, the outer phyllaries usually being less than 1/4, rarely to 1/3 as long as inner ones, the usual absence of an indumentum, the smaller number of flowers per head (5-15), the slender achenes with 10 thin, equal ribs and the chromosome number of x = 7.
Askellia comprises 11 species, which are distributed in SW, central and NE Asia and extend with two species into North America.
References
Babcock E. B. 1947: The genus Crepis. – Univ. Calif. Publ. Bot. 21-22.
Enke N. & Gemeinholzer B. 2008: Babcock revisited: new insights into generic delimitation and character evolution in Crepis L. (Compositae : Cichorieae) from ITS and i>matK sequence data. – Taxon 57: 756-768.
Kilian N., Gemeinholzer B. & Lack H. W. 2009: Tribe Cichorieae. – Pp. 343-383 in: Funk V., Susanna A., Stuessy T. & Bayer R. (ed.), Systematics and evolution of the Compositae. – Vienna: IAPT.
Pak J. H. & Bremer K. 1995: Phylogeny and reclassification of the genus Lapsana (Asteraceae : Lactuceae). – Taxon 44: 13-21.
Sennikov A. N. & Illarionova I. D. 2008 ["2007"]: Generic delimitation of the subtribe Ixeridinae newly segregated from Crepidiinae (Asteraceae-Lactuceae). – Komarovia 5: 57-115
Weber W. A. 1984: New names and combinations, principally in the Rocky Mountain flora IV. – Phytologia 55: 1-11.
Description
Herbs, perennial, usually rather delicate, with a slender taproot and often with shoot-bearing lateral roots. Stems rather low, slender, often branched from base. Leaves in basal rosette or along stem, usually small, with orbicular to obovate and spatulate blade attenuate into a long petiole-like base, glabrous. Synflorescence mostly with rather few capitula. Capitula erect, with 5–15 florets. Involucre narrowly cylindric. Phyllaries in few series, glabrous [or setulose or arachnoid hairy]; outer phyllaries usually less than 1/4, rarely to 1/3, as long as inner ones; inner phyllaries linear-lanceolate, equal. Receptacle naked. Florets yellow or more rarely pale purplish red. Achene usually pale brown, slenderly cylindric to slenderly fusiform, with 10 thin equal ribs, apically truncate, attenuate, or shortly beaked. Pappus white, of scabrid bristles, usually caducous or persistent.
from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 325. 2011, Beijing & St Louis.
from: Shih C. & Kilian N. in Wu Z. Y. & al. (ed.), Flora of China 20–21: 325. 2011, Beijing & St Louis.
Chromosome numbers
Diploids, x = 7.B
Distribution
Asia-Temperate: Afghanistan native; Altay native; Buryatiya native; China North-Central (Gansu native, Shanxi native); Chita native; Inner Mongolia (Nei Mongol native, Ningxia native); Iran native; Irkutsk native; Kamchatka native; Kazakhstan native; Khabarovsk native; Kirgizistan native; Krasnoyarsk native; Magadan native; Mongolia native; Qinghai native; Tadzhikistan native; Tibet native; Tuva native; Uzbekistan native; Xinjiang native; Yakutskiya native. Asia-Tropical: India (Uttar Pradesh native); Nepal native; Pakistan native; West Himalaya (Himachal Pradesh native, Jammu-Kashmir native). Northern America: Alaska native; Alberta native; British Columbia native; California native; Colorado native; Greenland native; Idaho native; Labrador native; Manitoba native; Montana native; Nevada native; Newfoundland (Newfoundland native); Northwest Territories native; Nunavut native; Ontario introduced; Oregon native; Saskatchewan reported in error; Utah native; Washington native; Wyoming native; Yukon native
Bibliography
B. Watanabe K.: Index to chromosome numbers in Asteraceae.. http://doi.org/10.18908/lsdba.nbdc02601-000