Chromosome number determinations in fam. Compositae, tribe Astereae. VIII. Eastern North American taxa. II

Rhodora ◽  
10.3119/14-05 ◽  
2015 ◽  
Vol 117 (969) ◽  
pp. 80-91 ◽  
Author(s):  
John C. Semple ◽  
Rachel E. Cook ◽  
Elliott Owen
Keyword(s):  
Chromosome Number ◽  
North American

CHROMOSOME NUMBER DETERMINATIONS IN FAMILY COMPOSITAE, TRIBE ASTEREAE. IX. NORTH AMERICAN TAXA. II

Rhodora ◽  
10.3119/18-07 ◽  
2019 ◽  
Vol 121 (985) ◽  
pp. 37 ◽  
Author(s):  
John C. Semple ◽  
Rachel E. Cook ◽  
Gary H. Morton ◽  
James B. Beck ◽  
Rita Lopez Laphitz
Keyword(s):  
Chromosome Number ◽  
North American

Chromosome numbers of 15 North American bumble bee species (Hymenoptera, Apidae, Bombini)

1983 ◽  
Vol 25 (1) ◽  
pp. 26-29
Author(s):  
Robin E. Owen
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Morphological Divergence ◽  
Chromosome Counts ◽  
Monophyletic Origin ◽  
The Social

Chromosome counts were obtained for 14 Bombus Latr. species (the social bumble bees) belonging to four subgenera and for one Psithyrus Lep. species (the social parasitic bumble bees). In Bombus the haploid numbers were consistent within each subgenus and there was variation between subgenera; the subgenera Bombus s.s. and Pyrobombus have n = 18, while Separatobombus and Cullumanobombus have n = 19. Thus considerable morphological divergence between subgenera is often, but not always, paralleled by divergence in chromosome number. Psithyrus ashtoni has n = 25, higher than all Bombus species yet examined. This provides support for the monophyletic origin of Psithyrus, but the high n is not expected if eusociality selects for increase in chromosome number.

The bearing of Phoxinus (Cyprinidae) hybridity on the classification of its North American species

1970 ◽  
Vol 48 (6) ◽  
pp. 1167-1177 ◽  
Author(s):  
Pierre Legendre
Keyword(s):  
Chromosome Number ◽  
Discriminant Function ◽  
North American ◽  
Parental Species ◽  
North American Species ◽  
Discriminant Functions

Three populations of Phoxinus eos × P. neogaeus were found to form single Mendelian populations, by comparison with the parental species through a discriminant function. The hybrids of one of these populations were found to be fertile. A fourth hybrid collection, studied by three discriminant functions, was found to contain Semotilus margarita, P. eos × P. neogaeus, and hybrids of S. margarita with at least P. eos, but possibly P. eos × P. neogaeus. The presence of this hybrid, when related to the chromosome number of the species concerned, suggests the transfer of S. margarita to the genus Phoxinus.

Biosystematics of the Perennial North American Taxa of Urtica. I. Chromosome Number, Hybridization, and Palynology

1982 ◽  
Vol 7 (3) ◽  
pp. 269 ◽  
Author(s):  
Dennis W. Woodland ◽  
I. John Bassett ◽  
Cliff Crompton ◽  
Suzanne Forget
Keyword(s):  
Chromosome Number ◽  
North American

The chromosome numbers of five North American and European leech species

1987 ◽  
Vol 65 (3) ◽  
pp. 681-684 ◽  
Author(s):  
Ronald W. Davies ◽  
R. N. Singhal
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Chromosome Numbers ◽  
Chromosome Evolution ◽  
Chromosome Counts ◽  
Prophase I ◽  
Metaphase I

Chromosome counts were obtained for four glossiphoniid species belonging to three genera (Glossiphonia, Theromyzon, Placobdella) and for one erpobdellid species (Dina lineata) of freshwater leeches. Theromyzon rude, which has a Palaearctic distribution, had seven bivalents at prophase I and metaphase I, while the Holarctic T. tessulatum had eight bivalents, giving diploid chromosome numbers of 14 and 16, respectively. Placobdella papillifera from Alberta had a chromosome number of 2n = 24 and Glossiphonia complanata from Alberta and England had chromosome counts of 2n = 28. At prophase I and metaphase I nine bivalents occurred in the majority of the nuclei of Dina lineata. These findings are discussed in relation to the chromosome evolution and phylogenetic schemes proposed by previous authors.

A TAXONOMIC STUDY OF WESTERN CANADIAN SPECIES IN THE GENUS BETULA

1966 ◽  
Vol 44 (7) ◽  
pp. 929-1007 ◽  
Author(s):  
Janet R. Dugle
Keyword(s):  
Gene Flow ◽  
Chromosome Number ◽  
North American ◽  
Parental Species ◽  
Environmental Influence ◽  
Taxonomic Study ◽  
Environmental Selection ◽  
First Time ◽  
Lower Chromosome Number

Five western North American birches, Betula fontinalis, B. glandulosa, B. glandulifera, B. resinifera, and B. papyrifera, are studied taxonomically. Four hybrids, B. × winteri, B. × sargentii, B. × arbuscula, and B. × uliginosa, are described for the first time and three others, B. × utahensis, B. × eastwoodae, and B. × sandbergii, are also included. Populations formed when species are in contact have been analyzed and the nature of several hybrid entities determined. B. × uliginosa results from B. resinifera × B. glandulifera. In this population, introgression is toward B. glandulifera, which has the higher chromosome number. B. glandulifera also hybridizes with B. glandulosa producing B. × sargentii. Most gene flow is toward B. glandulifera, which has the higher chromosome number. In B. glandulosa × B. fontinalis (B. × eastwoodae) introgression was little influenced by environmental selection, the hybrid was as common as either parental species, and any gene flow was in either direction. B. × utahensis results from B. papyrifera × B. fontinalis. Introgression is toward B. papyrifera. Hybridization of B. × sargentii and B. papyrifera produces B. × arbuscula, a rare hybrid. Hybridization of B. resinifera and B. papyrifera results in B. × winteri, with introgression in both directions. B. × sandbergii results from B. papyrifera × B. glandulifera. Probably as a result of environmental influence in the analysis area, introgression was toward B. glandulifera, with the lower chromosome number.

Karyotype of North American shortnose sturgeon Acipenser brevirostrum with the highest chromosome number in the Acipenseriformes

2005 ◽  
Vol 52 (1) ◽  
pp. 94-97 ◽  
Author(s):  
Dong Soo Kim ◽  
Yoon Kwon Nam ◽  
Jae Koo Noh ◽  
Chul Hong Park ◽  
Frank A. Chapman
Keyword(s):  
Chromosome Number ◽  
North American ◽  
Shortnose Sturgeon ◽  
Acipenser Brevirostrum

Cytotaxonomic observations on North American Festuca (Poaceae)

1992 ◽  
Vol 70 (10) ◽  
pp. 1940-1944 ◽  
Author(s):  
Susan G. Aiken ◽  
George Fedak
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
North American ◽  
West Coast ◽  
Chromosome Count ◽  
B Chromosomes ◽  
The Other ◽  
Festuca Rubra ◽  
Made In

The presence of B chromosomes is reported in Festuca altaica Trin., where a plant with relatively wide and often flat leaves had a chromosome number of 2n = 4x = 28; an adjacent plant, with conspicuously narrow and tightly rolled leaves, had 2n = 4x = 28 + 2B chromosomes. A first chromosome count of 2n = 42 is reported for Festuca rubra L. ssp. densiuscula (Hackel) Piper, along with observations on the nomenclature and morphology of this west coast subspecies. A first chromosome count for a North American plant of Festuca brevissima Jurtzev is 2n = 14. Collections made in northern Yukon were compared with the type borrowed from Leningrad and with the distribution of this species relative to the other North American diploid Festuca, Festuca aggr. auriculata Drob. A collection of Festuca brachyphylla Schultes from northern Yukon had a chromosome number of 2n = 42, and unusual morphology and phenology were interpreted as the result of a snow patch habitat. A second record for Festuca dasyclada Hackel ex. Beal of a chromosome number of 2n = 28 and justifications for keeping this species in Festuca are presented. Key words: Poaceae, North American, Festuca, chromosomes, morphology, nomenclature.

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