Content uploaded by John C. Semple
Author content
All content in this area was uploaded by John C. Semple on Jan 01, 2017
Content may be subject to copyright.
A preview of the PDF is not available
THE KARYOTYPE OF ASTER ERICOIDES (ASTERACEAE): SOME CANADIAN POPULATIONS
Abstract
Chromosome number determinations from five populations of Aster ericoides L. were either n = 5 or 2n = 10. Measurements of short and long arms of each pair of chromosomes are given. Previous reports of the chromosome number of the species are discussed. Some aneuploidy may be occurring in the species.
... Cytogeography based on reports in Delisle (1937), Wetmore and Delisle (1939a), Van Faasen (1963), Löve and Löve (1964, 1982), Semple (1976, 1981, 1985), Jones (1978a, b, c), Semple and Brouillet (1980a), Chmielewski and Semple (1985), Semple et al. (1989, 1992). 2n = 10, 2n = 20. ...
Symphyotrichum ericoides, the heath aster, is a herbaceous perennial, arising from woody, corm-like rootstocks or herbaceous rhizomes. This facultative upland species occurs in open, dry ground in plains, railway sidings, prairies, ranges, glades, grassy hillsides, dunes, sand bars, river banks, shore salt flats, and thickets. A weed in Canada, and sometimes declared so in the United States and other times not, S. ericoides has an extensive North American distribution, occurring from Nova Scotia and Maine in the east, westward to southem British Columbia, and southward to northern Mexico. No infraspecific taxa are recognized in this treatment of the species. Symphyotrichum novae-angliae, the New England aster, is a herbaceous perennial, arising from thick, short-branched, woody root-stocks. This facultative wetland species occurs in open places such as along roadside ditches and fence rows, on dry ground in plains, prairies and glades, in clearings, meadows and abandoned fields, and along stream banks and swamps, or in moist open or sometimes wooded places. A weed in both Canada and the United States, S. novae-angliae occurs commonly throughout the northem two-thirds of the eastern deciduous forest region of North America and onto the Great Plains. In the east, Nova Scotia populations are likely escaped cultivars, but in the west, isolated natural populations occur from the Black Hills region of South Dakota south to New Mexico. No infraspecific taxa are recognized in this treatment of the species. In those habitats where the two species co-occur, the morphologically intermediate F1 hybrid S. amethystinum is often found.
Chromosome counts are presented for more than 250 populations ofAster representing 56 species and eight spontaneous interspecific hybrids. Species are listed according to the infrageneric classification
system presented in the preceding paper which utilizes basic chromosome numbers as the pivotal diagnostic character. Fundamental
to the classification is an ecological species concept. The list is augmented by a series of comments on field observations
and on the examination of types. Six older names previously placed in synonymy or recognized at an inferior rank are reinstated
at the species level:A. brachypholis, A.firmus, A. fragilis, A. longifolius, A. simmondsii andA. tardiflorus. Two taxa included as species in current manuals of the eastern North American flora are reduced in status to subspecies rank
underA. cordifolius. Putative hybrid status is assigned to four taxa previously treated and originally published as species:A. × coerulescens (= A. praealtus × A. simplex, A. × interior (= A. simplex × A. tradescantii, A. × maccallae (= A. ciliolatus
× A. subspicatus) and A. × subgeminatus (= A. ciliolatus × A. tardiflorus). With new data available, the basic chromosome number ofx = 8 has now been confirmed for all species ofAster sectionHeterophylli, except the Mexican A.coahuilensis.
Huziwara, Y. (Kobe U., Mikage, Kobe, Japan.) Karyotype analysis in some genera of Compositae. VIII. Further studies on the chromosomes of Aster. Amer. Jour. Bot. 49 (2) : 116–119. Illus. 1962.—The karyotypes of 3 Asiatic and 3 American taxa of Aster are reported here for the first time. These are: A. ageratoides subsp. sugimotoi (Kitamura) Kitamura 2n = 36, A. ageratoides subsp. (Taxon AIII) 2n = 72, A. himalaicus C. B. Clarke 2n = 18, A. ericoides L. 2n = 32, A. meritus A. Nels. 2n = 27, A. umbellatus Mill. 2n = 18. Two American taxa, namely, A. meritus and A. umbellatus, are considered to be ancestral taxa which have retained primitive karyotypes similar to those of Asiatic species of Aster.
Reports of 129 new chromosome counts are made for the tribe Astereae of Compositae. They are mostly based on determinations of meiotic material, including first counts for one genus and 43 species or subspecies. Counts are now available for more than 63 of the 100-120 genera and 564 of the approximately 2,000 species in the tribe. Three of every four genera with more than one species counted show more than one chromosome number; 15 genera have species with populations with different numbers. Such variation is very high and indicates the need for more detailed cytotaxonomical study in the group.
Chromosome numbers of flowering plants
- A Hederov
Hederov, A. 2968. Chromosome numbers of flowering plants. Acad. Sci. USSR, Komuov Botanical
Institute, Leningrad.
Studies in the genetics m d cytology of two species in the genus Aster and their polymorghy in nature
- R Wetmore
- A Delisle
Wetmore, R. and Delisle, A. 1939.. Studies in the genetics m d cytology of two species in the genus Aster
and their polymorghy in nature. Am. J. Bot. 26: 1-12.
Karystype analysis in some genera s f Compositae. VIIH. Further studies on the chromosomes of
- Y Hurizawa
Hurizawa, Y. 1962. Karystype analysis in some genera s f Compositae. VIIH. Further studies on the
chromosomes of Aster. Am. 5. Bot. 49: 1 16-B 89.