CYTOTAXONOMY OF THE SPECIES AND INTERSPECIFIC HYBRIDS OF THE GENUS ELYMUS IN CANADA AND NEIGHBORING AREAS

1964 ◽  
Vol 42 (5) ◽  
pp. 547-601 ◽  
Author(s):  
Wray M. Bowden

A cytotaxonomic treatment is given for 12 native species, 2 introduced species, and 3 natural interspecific hybrids of the genus Elymus L. that occur in Canada. Five of the native Elymus species and an additional natural interspecific hybrid are found in Alaska. Eleven of the native species, one introduced species, and two of the natural interspecific hybrids are present in the mainland United States. Some additional native species and natural interspecific hybrids of Elymus from the mainland United States are treated briefly.Nomenclatural proposals include: Elymusglaucus Buckl. var. virescens (Piper) Bowden; E. ×uclueletensis Bowden (E. mollis Trin. f. mollis × E. glaucus Buckl. var. glaucus); E. × aleuticus Hultén (pro sp.) (E. mollis Trin. f. mollis × E. hirsutus Presl); E. canadensis L. var. wiegandii (Fern.) Bowden f. wiegandii and f. calvescens (Fern.) Bowden; E. ×maltei Bowden nm. maltei, nm. simulans Bowden, nm. churchii Bowden, and nm. brownii Bowden (E. virginicus L. × E. canadensis L.); E. virginicus L. var. jenkinsii Bowden; E. hystrix L. var. bigelovianus (Fern.) Bowden; E.piperi Bowden; E. innovatus Beal subsp. innovatus var. glabratus Bowden; and E. triticoides Buckl. var. pacificus (Gould) Bowden. Hystrixpatula Moench is here treated as Elymushystrix L.Voucher specimens are cited for the following chromosome number determinations:(1) diploid, 2n = 14: Elymusjunceus.(2) tetraploid, 2n = 28: Elymus canadensis var. canadensis, E. canadensis var. wiegandii f. wiegandii, E. diversiglumis, E. glaucus var. glaucus, E. glaucus var. virescens, E. hirsutus, E, hystrix var. hystrix, E. hystrix var. bigelovianus, E. innovatus subsp. innovatus var. innovatus, E. × maltei nm. maltei, E. riparius, E. sibiricus, E. villosus f. villosus, E. virginicus var. virginicus f. virginicus, and E. virginicus var. submuticus.Earlier literature reports (based on voucher specimens) are given for the following:(1) tetraploid, 2n = 28: Elymus mollis (two subsp. and three forms), E. piperi, and E. × vancouverensis nm. crescentianus.(2) hexaploid, 2n = 42: Elymus × vancouverensis nm. vancouverensis, and E. × vancouverensis nm. californicus.(3) octoploid, 2n = 56: Elymus arenarius, E. innovatus subsp. velutinus, and E. piperi.

1965 ◽  
Vol 43 (11) ◽  
pp. 1421-1448 ◽  
Author(s):  
Wray M. Bowden

A cytotaxonomic treatment is given for 10 native species, 4 introduced species, and 8 natural interspecific hybrids of the genus Agropyron Gaertner that occur in Canada. Five of the native Agropyron species, one introduced species, and one natural interspecific hybrid are also found in Alaska. Eight of the native species, the four introduced species, and four natural interspecific hybrids are present in the mainland United States. Four additional native species and five additional introduced species that occur in the mainland United States are considered briefly.Nomenclatural proposals include: Agropyron dasystachyum (Hook.) Scribn. var. riparium (Scribn. & Smith) Bowden; Agropyron × pseudorepens Scribn. & Smith (pro sp.) nm. pseudorepens and nm. vulpinum (Rydb.) Bowden (A. dasystachyum × A. trachycaulum); and Agropyron × brevifolium Scribn. (pro sp.) (A. scribneri × A. violaceum).Voucher specimens are cited for chromosome number determinations of the native and introduced Agropyron species and some natural and artificial interspecific hybrids. Chromosome numbers are reported for the first time for A. violaceum (2n = 28), A. yukonense (2n = 28), the natural hybrids A. × pseudorepens nm. pseudorepens and nm. vulpinum (2n = 28), A. dasystachyum × A. spicatum (2n = 21), and A. violaceum × A. yukonense (2n = 28), and four artificial interspecific hybrids. Seven natural hybrids and four artificial hybrids are reported for the first time.


1986 ◽  
Vol 28 (6) ◽  
pp. 947-953 ◽  
Author(s):  
Richard R. -C. Wang ◽  
C. Hsiao

Hybrids of Elymus canadensis (2n = 28; SSHH) × Critesion californicum (2n = 14) and E. canadensis × C. bulbosum (2n = 14) were synthesized at relative frequencies of 11.8 and 0.3%, respectively, by the aid of embryo rescue techniques. A natural hybrid was identified as C. violaceum × C. bogdanii (2n = 14) by a combination of karytotype analysis and plant morphology. Gross spike morphology of the hybrids was intermediate to that of the parents. Meiotic chromosome pairings in these hybrids suggested that the genome of C. californicum and C. bogdanii is more or less homologous with one of the two genomes of E. canadensis. Genomes of C. violaceum and C. bulbosum appeared to be different from each other and from those in C. bogdanii and C. californicum. Based on the data in this study and others, the degree of genome differentiation among some Critesion and some Elymus species containing the H genome was examined and discussed. The symbol H is proposed for the genome in C. bogdanii and C. californicum, Hv for C. violaceum, Hb for C. bulbosum, and Hc for C. chilense.Key words: interspecific hybrids, synapsis, phylogeny, Hordeum, Elymus, Critesion.


1969 ◽  
Vol 47 (8) ◽  
pp. 1257-1275 ◽  
Author(s):  
R. J. Moore ◽  
C. Frankton

The morphology and chromosome number of nine species of Cirsium of eastern North America are considered. Chromosome counts are presented for the first time for C. iowense, 2n = 18; C. lecontei, 2n = 32; C. nuttallii, 2n = 24, 28; C. repandum, 2n = 30; C. smallii, 2n = 34; C. engelmannii, 2n = 20; C. texanum, 2n = 22, 24; C. virginianum, 2n = 28. Additional chromosomes, possibly to be considered as accessories, were found in C. nuttallii, C. engelmannii, and C. texanum. These chromosomes render uncertain the number characteristic of these species. A key to the 26 native and introduced species found in Canada and the United States east of 100° west latitude is presented. The interrelationships of the eastern species and of the species of the western series Undulata are discussed.


Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 150-155 ◽  
Author(s):  
J. Torabinejad ◽  
J. G. Carman ◽  
C. F. Crane

Sexual, hexaploid (2n = 42) Elymus scabrus (R. Br.) A. Löve (formerly Agropyron scabrum (R. Br.) Beauv.) was used as the male parent for crossability studies and genome analysis of this Australian species. Mean number of paired chromosome arms (PA) and mean number of chromosome associations per metaphase I cell were determined for four different interspecific hybrids. Means by the female parent of each interspecific hybrid were as follows: tetraploid Elymus canadensis L., 1.17 PA and 32.76 I + 0.04 II (ring) + 1.08 II (rod) + 0.005 IV (chain) in 179 cells from four F1's; hexaploid Elymus tsukushiensis Honda, 14.13 PA and 23.48 I + 4.69 II (ring) + 4.13 II (rod) + 0.27 III + 0.01 IV (ring) + 0.01 IV (rod) in 140 cells from three F1's; tetraploid Elymus longearistatus (Boiss.) Tzvelev, 4.20 PA and 27.53 I + 0.39 II (ring) + 3.12 II (rod) + 0.15 III in 59 cells from one F1; and tetraploid Elymus semicostatus (Nees ex Steud.) A. Löve, 3.98 PA and 27.961 + 0.34 II (ring) + 2.86 II (rod) + 0.16 III + 0.04 IV (chain) in 50 cells from one F1. All F1's were completely sterile. An amphiploid of F1 E. tsukushiensis – E. scabrus was obtained by 0.1% colchicine treatment. It was partially sterile and had the expected chromosome number of 2n = ca. 84. The data were interpreted to indicate that E. scabrus lacks the S and H genomes of E. canadensis, contains the Y genome and a modification of another genome of E. tsukushiensis, and a modification of the Y genomes of E. longearistatus and E. semicostatus. These results contradict a previous report of an S and H genome composition for the Australasian wheatgrasses. Key words: apomixis, Elymus canadensis, Elymus longearistatus, Elymus semicostatus, Elymus tsukushiensis.


2010 ◽  
Vol 26 (3) ◽  
pp. 347-350 ◽  
Author(s):  
Jannie Fries Linnebjerg ◽  
Dennis M. Hansen ◽  
Nancy Bunbury ◽  
Jens M. Olesen

Disruption of ecosystems is one of the biggest threats posed by invasive species (Mack et al. 2000). Thus, one of the most important challenges is to understand the impact of exotic species on native species and habitats (e.g. Jones 2008). The probability that entire ‘invasive communities’ will develop increases as more species establish in new areas (Bourgeois et al. 2005). For example, introduced species may act in concert, facilitating one another's invasion, and increasing the likelihood of successful establishment, spread and impact. Simberloff & Von Holle (1999) introduced the term ‘invasional meltdown’ for this process, which has received widespread attention since (e.g. O'Dowd 2003, Richardson et al. 2000, Simberloff 2006). Positive interactions among introduced species are relatively common, but few have been studied in detail (Traveset & Richardson 2006). Examples include introduced insects and birds that pollinate and disperse exotic plants, thereby facilitating the spread of these species into non-invaded habitats (Goulson 2003, Mandon-Dalger et al. 2004, Simberloff & Von Holle 1999). From a more general ecological perspective, the study of interactions involving introduced and invasive species can contribute to our knowledge of ecological processes – for example, community assembly and indirect interactions.


1975 ◽  
Vol 17 (2) ◽  
pp. 253-262 ◽  
Author(s):  
J. H. Hunziker ◽  
L. Poggio ◽  
C. A. Naranjo ◽  
R. A. Palacios ◽  
A. B. Andrada

Cytological results on 12 species and 4 putative hybrids of Prosopis are presented. Of these, 5 species and 4 hybrids have been hitherto unknown cytologically. The following species proved to be diploid (2n = 28) and constitute new chromosome number determinations for the genus: P. algarobilla Griseb., P. hassleri Harms, P. nigra (Griseb.) Hieron., P. patagonica Speg., P. tamarugo Phil. The diploid nature of some races of P. juliflora (Sw.) DC. is established; apparently under this taxon there are also tetraploid populations. The following putative interspecific hybrids showed regular meiosis with formation of 14 bivalents: P. vinalillo Stuck. (P. ruscifolia × P. alba?), P. alba × P. nigra? and P. hassleri × P. ruscifolia?.So far 28 taxa of the genus have been studied cytologically; 27 of these are diploid. The scarcity of polyploidy in the genus (3.5%) might be a consequence of the almost general lack of means of vegetative reproduction and of the absence of chromosome repatterning in primary speciation. Results of other authors concerning cytological data are also discussed.


2021 ◽  
Vol 41 (3) ◽  
pp. 358-366
Author(s):  
Peter B. Banks

Distinguishing between whether a species is alien or native can be problematic, especially for introduced species that are long-established in new areas outside of their natural range. Transport by humans is the criterion for alien status used by many definitions, whereas arbitrary time since arrival to a location is often used to define native status. Here I propose an eco-evolutionary approach to distinguish between alien and native status and use this to resolve uncertainty in the status of the dingo in Australia. Dingoes were transported to mainland Australia by humans, but more than 4000 years ago, and dingoes now interbreed with feral domestic dogs. Legally, this mix of events has the dingo classified as native in some jurisdictions and alien in others. I suggest that native status for introduced species should be based on (1) whether the species has evolved in their new environment; (2) whether local species recognise and respond to them as they do towards deep endemic native species, and; (3) whether their impacts benchmark against those of a native species or are exaggerated like those of other alien species. Dingoes are behaviourally, reproductively and morphologically different to close ancestors from south-east Asia, and this difference has a genetic basis indicative of evolution in Australia. There is abundant evidence that native prey species on mainland Australia recognise and respond to them as a dangerous predator, which they are. But there is strong evidence that dingo impacts on prey are not exaggerated, with effect sizes from mensurative experiments similar to those of experiments on native predators rather than alien predators. These three lines of evidence suggest dingoes should be considered native to mainland Australia. I suggest this eco-evolutionary approach to defining native status can be helpful in resolving the often-heated debates about when an alien species becomes native.


2011 ◽  
Vol 25 (2) ◽  
pp. 346-362
Author(s):  
Edson Luís de Carvalho Soares ◽  
Márcia Vignoli-Silva ◽  
Lilian Auler Mentz

This work consists of a taxonomic synopsis of the genera of Solanaceae in Rio Grande do Sul state, Brazil. Solanaceae is represented by 28 genera in this state: Acnistus Schott, Athenaea Sendtn., Aureliana Sendtn., Bouchetia Dunal, Browalia L., Brugmansia Pers., Brunfelsia L., Calibrachoa La Llave & Lex., Capsicum L., Cestrum L., Datura L., Dyssochroma Miers, Grabowskia Schltdl., Jaborosa Juss., Lycianthes (Dunal) Hassl., Melananthus Walp., Nicandra Adans., Nicotiana L., Nierembergia Ruiz & Pav., Petunia Juss., Physalis L., Salpichroa Miers, Schwenckia L., Sessea Ruiz & Pav., Solandra Sw., Solanum L. (including Cyphomandra Sendtn. and Lycopersicon Mill.), Streptosolen Miers and Vassobia Rusby. Of these, 23 consist of native species , while five are represented exclusively by introduced species. The total number of species is 149, of which 118 are native and 31 are introduced (adventitious or cultivated). An identification key for genera, and also comments on the most relevant taxonomic characters of each one are presented, plus comments on the species that occur in Rio Grande do Sul state.


2021 ◽  
Vol 210 (07) ◽  
pp. 2-15
Author(s):  
Liliya Beksheneva ◽  
Antonina Reut

Abstract. The article presents the results of an experimental assessment of the peculiarities of the water regime of 9 species of the genus Iris L. growing in the South-Ural Botanical Garden-Institute UFRC RAS (I. sibirica L., I. pseudacorus L. ‒ species of native flora, I. aphylla L., I. biglumis Vahl., I. lacteal Pall., I. orientalis Mill., I. ruthenica Ker-Gawl., I. setosa Pall., I. spuria L. ‒ introduced species). The purpose is a comparative evaluation of the main parameters of the water regime within the generic complex and depending on the detection of meteorological factors in different phenological periods. Methods. Studies were performed in growing periods 2019–2020’s physiological using conventional techniques (artificial saturation method and wilting). Made a detailed analysis of daily and seasonal dynamics of the water regime of the three parameters: the total water content, water-holding capacity, water scarcity. Typical forest species Convallaria majalis L. was investigated for a comparative analysis of water regime indicators. Results. The similarities and differences in the peculiarities of the water regime were established between the studied species, the dependence of the indicators on meteorological conditions was revealed. According to the type of water regime cultivars were divided into four groups: a flexible water-quiet mode ‒ I. pseudacorus, flexible water-tight mode ‒ I. sibirica, I. ruthenica, stably-calm water mode ‒ I. aphylla, I. biglumis, I. setosa, stably-tight water mode ‒ I. spuria, I. lactea, I. orientalis. Among the studied parameters of water scarcity was the most dependent on meteorological factors. Scientific novelty. The study helps to identify ecological and physiological adaptations of exotic species in comparison with the native species that could become the basis for assessing the prospects of growing in the culture and conservation of rare and endangered species.


<em>Abstract</em>.—Rivers and streams of the southern United States contain more than 1,800 aquatic species, 500 of which are regionally endemic. At present, 34% of the fish species and 90% of the mussel species in peril nationwide are found in these systems. Declines in these imperiled species are due to many factors, including hydrologic alteration, degraded water quality, loss of instream and watershed connectivity, physical habitat degradation, and the negative effects of nonindigenous species (e.g., predation on, competition with, and hybridization with native forms). In addition, this situation is exacerbated through human population growth, competing water demands, land-use changes, and other interrelated issues. If unchecked, these issues will likely continue to contribute to the imperilment and loss of native species in the region. Of the nine described species and subspecies of black bass, six are endemic to the southern United States: Guadalupe Bass <em>Micropterus treculii</em>, Shoal Bass <em>M. cataractae</em>, Redeye Bass <em>M. coosae</em>, Florida Bass <em>M. floridanus</em>, Alabama Bass <em>M. henshalli</em>, and Suwannee Bass <em>M. notius</em>. In addition, undescribed species and subspecies also exist and all are in need of conservation measures to prevent them from becoming imperiled. In an effort to focus and coordinate actions to support the long-term persistence of endemic black bass populations, local, state, and federal agencies, universities, nongovernmental organizations, and corporations from across the region joined with the National Fish and Wildlife Foundation to form the Native Black Bass Initiative (NBBI). The NBBI provides regional conservation strategies, objectives, and targets to restore and preserve functional processes in those watersheds that support natural habitat conditions and sustainable populations of endemic black bass and other native fishes of the region. Initial actions implemented through the NBBI focus on addressing the conservation needs of Guadalupe Bass in streams of the Edwards Plateau ecoregion of Texas, Redeye Bass in the Savannah River watershed of Georgia and South Carolina, and Shoal Bass populations in the Apalachicola River watershed of Alabama, Florida, and Georgia.


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