Index of chromosome numbers of Tasmanian spermatophytes

Abstract

A preliminary index of chromosome numbers for spermatophytes indigenous ro Tasmania is presented, with reference citations. This compilation includes reports for 166 species provenanced from Tasmanian material, many previously published, and also 55 unpublished results (mostly from the work ofWDJ). Selected reports of species indigenous to Tasmania but derived elsewhere (usually material from New Zealand or the Australian mainland) are also included as a basis for further study. In total, chromosome numbers are listed for 400 species (409 taxa, including subspecies and varieties) out of a total estimated spermatophyte fl ora of 1568 described indigenous species. Ten of the 108 families have been examined in some detail (> 45% of species), but the four most speciose families (625/1568 species; Orchidaceae, Asteraceae, Poaceae and Cyperaceae) have a total of only four Tasmanian reports, despite highly variable chromosome com plements. Five other speciose families (Apiaceae, Brassicaceae, Juncaceae, Rhamnaceae and Scrophulariaceae) have no Tasmanian reports despite demonstrating cytological variability at generic, inter-and intra-specific levels. Further cytological investigation of these taxa is essential for a clearer understanding of the Tasmanian fl ora.

Chromosome number of two Chilean species of Nothofagus (Nothofagaceae)

“…Oerst. from Tasmania (Armstrong & Wylie 1965, Wardle 1967, Ono 1977, Dawson 2000, Wiltshire & Jackson 2003. These results increase to 13 the species of Nothofagus with available chromosome data (36% of the genus), which represent all four subgenera proposed by Hill & Read (1991) (e.g., Lophozonia, Fucospora, Nothofagus, and Brassospora).…”

“…On the basis of multiple lines of evidence compiled in later decades the first hypothesis was discard (Hill & Jordan 1993, Manos & Stanford 2001. Regarding the second hypothesis, it may be supported by the current cytogenetic evidence available for Nothofagus which shows that one species has 28 chromosomes (N. cunninghamii with x = 14), being included within the subgenus Lophozonia together with other species having 26 chromosomes (Dawson 2000, Wiltshire & Jackson 2003. Thus, the existence of an ancestor with x = 14 chromosomes is possible, which may be closest to N. cunninghamii.…”

“…However, despite these advances, some aspects on the evolution of Nothofagus remain obscure, for example, the mechanism on chromosome evolution related with the origin of the genus and species differentiation. On this respect, chromosome numbers and/or qualitative karyotype studies have been previously reported for 11 species of Nothofagus (30.5% of the species of the genus), seven of them inhabit various countries from Oceania (Armstrong & Wylie 1965, Wardle 1967, Ono 1977, Carr & McPherson 1986, Oginuma et al 1998, Wiltshire & Jackson 2003, and four occurring in Chile (Ono 1977) (Table I). The most frequent chromosome number described within the genus is 2n = 26 (Ono 1977, Dawson 2000, although one species from Oceania has been reported having a diploid number of 2n = 28 (N. cunninghamii (Hook.)…”

“…Oerst. ; Wiltshire & Jackson 2003). Interestingly, all four Chilean species studied so far show a diploid chromosome number 2n = 26.…”

Understanding the extensive hybridization in South American Nothofagus through karyotype analysis

“…Oerst. with 2n = 2x = 28 (Wiltshire & Jackson, 2003). Chromosome numbers for N. nervosa, N. antarctica, N. dombeyi, N. glauca, N. obliqua and N. pumilio are here confirmed (Ono, 1977;Jara-Seguel et al, 2014), whereas those for N. alessandrii, N. betuloides, N. macrocarpa and N. nitida are reported for the first time.…”