Chromosome numbers and karyotypes in the Australian Gnaphalieae and Plucheeae (Asteraceae)

Abstract

Chromosome number determinations from 152 collections representing 42 genera and 106 species of the Australian Gnaphalieae and Plucheeae are reported. The chromosome numbers of 75 of these species have not been previously counted or differ from those previously reported for species. Chromosome numbers have been documented for the first time for 14 genera: Argyroglottis (n = 12), Cephalosorus (2n = 24), Decazesia (n = 14), Dielitzia (2n = 26), Eriochlamys (n = 14), Erymophyllum (n = 11 and 14), Gilruthia (n = 13), Leucochrysum (n = 9), Myriocephalus s. str. (n = 14, 2n = 24), Polycalymma s. str. (n = 14), Pterocaulon (n = 10), Pterochaeta (n = 12), Quinetia (2n – 24) and Sondottia (2n = 6). Remaining counts augment and agree with previously reported determinations. Some problems with generic delimitation and interpretation of chromosome data are outlined. There is an array of karyotypes within the Australian Gnaphalieae and dysploidy is widespread. Polyploidy has also played an important role in the evolution of some taxa. Evidence suggests that the base number for Australian Gnaphalieae is x = 14. This may be the base number for the entire tribe.

A karyotypic study of three southern Brazilian Asteraceae species using fluorescence in situ hybridization with a 45S rDNA probe and C-CMA3 banding

“…In some cases, the karyotypes of Asteraceae, such as those belonging to the Gnaphalieae group (Watanabe et al, 1999b), can vary considerably in number, from 2n = 6 in Podolepis to 2n = 120 in Craspedia, and in symmetry, from unimodal in Podotheca to bimodal in Schoenia. Thus, the karyotype differences observed among Crepis japonica, Galinsoga parviflora and Chaptalia nutans appear to be common in the Asteraceae family.…”

Cytogenetics of Chilean angiosperms: Advances and prospects

“…In addition, an important compilation is also available for Paraguay where almost 313 species of its fl ora have been citogenetically studied (Molero et al 2001). For other zones of South America (Central and Eastern Brazil) and Oceanía (Australia, Tasmania) despite the extensive studies on cytogenetic of plants, statistical estimations on the total number of examined species are not available (Jackson 1958, Smith-White 1959, Coleman 1982, Carvalheira et al 1991, Watanabe et al 1999, Forni-Martins & Martins 2000.…”

Chromosome numbers and polyploidy inLeontopodium(Asteraceae: Gnaphalieae) from the Qinghai-Tibet Plateau of S.W. China

“…Most genera of the Gnaphalieae have chromosome numbers that are multiples of 7 (Merxmüller et al 1977;Anderberg 1994;Watanabe et al 1999). However, n = 14 or 2n = 28 is the most frequent number in the tribe and Watanabe et al (1999) suggested x = 14 as the possible base number of the tribe.…”

“…However, n = 14 or 2n = 28 is the most frequent number in the tribe and Watanabe et al (1999) suggested x = 14 as the possible base number of the tribe. In Leontopodium, the chromosome number were reported as n = 12, 14 or 2n = 26, 48, 49, 52, 73 (Siljak 1977;Krogulevich 1978;Murin and Paclova 1979;Zhukova 1980;Krasnikova et al 1984;Nishikawa 1985;Vir Jee and Kachroo 1985;Khatoon and Ali 1988), and our results are 2n = 24, 28, 48, 52 and 72.…”