The systematics of Clarkia, section Myxocarpa

1971 ◽  
Vol 49 (7) ◽  
pp. 1211-1217 ◽  
Author(s):  
Ernest Small
Keyword(s):  

Two previously described diploid species in Clarkia, section Myxocarpa, have been found to comprise five allopatric groups, which are reproductively isolated by very strong chromosomal sterility barriers, and are divergent ecologically. Two of these groups are each made up of a pair of distinctive races. All of these are extremely difficult to distinguish morphologically, although consistent differences have been found. Emphasizing reproductive, ecological, and distributional criteria, these have been recognized as five species, two of which are composed of a pair of subspecies. The relationships of the proposed taxa to the other two species of section Myxocarpa are examined, and the problem of treating the group taxonomically is considered.


PhytoKeys ◽  
2019 ◽  
Vol 115 ◽  
pp. 51-57 ◽  
Author(s):  
Jordan R. Brock ◽  
Terezie Mandáková ◽  
Martin A. Lysak ◽  
Ihsan A. Al-Shehbaz

Camelinaneglecta is described as a new diploid species and its relationship to the other diploids of the genus and to the somewhat superficially similar tetraploid C.rumelica and hexaploid C.microcarpa, are discussed. SEM of seed and stem trichomes of the new species are presented.



Phytotaxa ◽  
2021 ◽  
Vol 522 (1) ◽  
pp. 27-37
Author(s):  
DANIEL F. BRUNTON ◽  
MICHAEL GARRETT ◽  
PAUL C. SOKOLOFF ◽  
GINTARAS KANTVILAS

Isoetes jarmaniae sp. nov. is described as a new lycophyte endemic to Tasmania, Australia, where it is confined to peat-bound karstic wetlands in several river valleys in the south-west wilderness. While seemingly morphologically closest to I. drummondii, this quillwort has features that are globally uncommon in Isoetes and unknown in other Australasian taxa. Most notable are its markedly flattened, strongly recurved leaves and disproportionately large sporangium ligules that are more suggestive of South American than Australian taxa. As well, the exceptionally thin and wide (alate) megaspore equatorial ridge is swollen at suture intersections, presenting a slightly triangular shape suggestive of the Indian taxon I. udupiensis. The microspores of I. jarmaniae exhibit exceptionally, perhaps uniquely, fine-papillate ornamentation. An original key placing I. jarmaniae in context with the other Tasmanian Isoetes species is provided. This diminutive, apparently diploid species is evidently maintaining a self-sustaining population within a regionally unique habitat and small geographic range.



1983 ◽  
Vol 8 ◽  
pp. 101-126 ◽  
Author(s):  
G. Vida ◽  
A. Major ◽  
T. Reichstein

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.



1958 ◽  
Vol 36 (4) ◽  
pp. 539-546 ◽  
Author(s):  
Priyabrata Sarkar

Five species are included in the genus Eremopyrum, namely, E. triticeum, E. hirsutum, E. buonapartis, E. orientale, and E. distans. Of these, the first two are diploids with 2n = 14, while the rest are tetraploids with 2n = 28. The karyotypes of the two diploid species are different from those of any other member, of the Triticineae in that they have chromosomes with extremely subterminal centromeres. The karyotype of each of the three tetraploid species shows a mixture of two types of chromosomes: seven pairs with extreme subterminal centromeres and the other seven pairs with median or submedian centromeres. This indicates that these are amphidiploids between triticeum–hirsutum-like taxa and perhaps some diploid species of crested Agropyron. In view of the karyotypic peculiarity, annual habit, and reported sterility barrier, the decision to give Eremopyrum generic status is supported.



1970 ◽  
Vol 48 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Alejandra M. Ortíz ◽  
María C. Silvestri ◽  
Graciela I. Lavia

Summary: Karyotypes of three diploid species belonging to sections Erectoides (Arachis hermannii), Procumbentes (A. rigonii) and Rhizomatosae (A. burkartii) were analyzed by Feulgen’s technique. The karyotype formula was different in each of the taxa analyzed: 2n=2x=16m+4sm in A. hermannii, 2n=2x=18m+2sm in A. rigonii, and 2n=2x=20m in A. burkartii. All species had a pair of satellited chromosomes, which corresponded to type 2 in A. hermannii, type 9 in A. rigonii, and type 8 in A. burkartii. Arachis hermannii and A. rigonii presented chromosomal features similar to those of the other species included in their respective sections. However, A. burkartii showed chromosome characteristics different from those found in the rest of the species of section Rhizomatosae.Key words: Arachis hermannii, A. rigonii, A. burkartii, chromosomes, phylogenetic relationships.Resumen: Estudios cariotípicos en especies silvestres de Arachis (Leguminosae) pertenecientes a las secciones Erectoides, Procumbentes y Rhizomatosae. Los cariotipos de tres especies diploides pertenecientes a las secciones Erectoides (A. hermannii), Procumbentes (A. rigonii) y Rhizomatosae (A. burkartii) fueron analizados mediante la técnica de Feulgen. Las fórmulas cariotípicas obtenidas son diferentes en los taxones analizados, 2n=2x=16m+4sm en A. hermannii, 2n=2x=18m+2sm en A. rigonii, y 2n=2x=20m en A. burkartii. Las tres especies presentaron un par de cromosomas con satélite, en A. hermannii tipo 2, en A. rigonii tipo 9 y en A. burkartii tipo 8. Arachis hermannii y A. rigonii presentaron características cromosómicas similares a las especies incluidas en sus respectivas secciones. Sin embargo, A. burkartii no comparte características cromosómicas con el resto de las especies de la sección Rhizomatosae.Palabras clave: Arachis hermannii, A. rigonii, A. burkartii, cromosomas, relaciones filogenéticas.



1979 ◽  
Vol 27 (6) ◽  
pp. 713 ◽  
Author(s):  
E Putievsky ◽  
P Broue

A cytogenetic analysis based on F1 hybrids of some of the perennial species of Glycine subgenus Glycine Verdc. shows that G. clandestina and G. canescens are closely related and further, that either one of these diploid species could have provided one genome for the tetraploid form of G. tomentella. On the other hand, it appears that G. falcata and G. tabacina are distinctive species which are not closely related to the other three species. The tetraploid form of G. tomentella is genetically heterogeneous and crosses between certain types yield F1s with low pollen stainability which fail to set seed under conditions of self-fertilization.



Genome ◽  
1987 ◽  
Vol 29 (6) ◽  
pp. 891-893 ◽  
Author(s):  
H. Lucas ◽  
J. Jahier

The number of associations between chromosome arms in the pollen mother cells of the hybrid Triticum boeoticum × T. urartu is similar to that in the pollen mother cells of the parental accessions. The latter two species were crossed with the following diploid species: T. tauschii, T. comosum, T. umbellulatum, and Haynaldia villosa. The meiotic behaviour of the hybrids showed that the chromosomes of T. urartu share more homology with the diploid Triticum species than do those of T. boeoticum. On the other hand, there is more pairing in the hybrid T. boeoticum × H. villosa than in T. urartu × H. villosa. These results confirm that T. boeoticum and T. urartu are distinct species. Key words: Triticineae, interspecific hybrids, meiotic behaviour, speciation.



Genome ◽  
2001 ◽  
Vol 44 (4) ◽  
pp. 685-690 ◽  
Author(s):  
A Benabdelmouna ◽  
Y Shi ◽  
M Abirached-Darmency ◽  
H Darmency

Genomic in situ hybridization (GISH) was used to investigate genomic relationships between different Setaria species of the foxtail millet gene pool (S. italica) and one interspecific F1 hybrid. The GISH patterns obtained on the two diploid species S. viridis (genome A) and S. adhaerans (genome B), and on their F1 hybrid showed clear differentiation between these two genomes except at the nucleolar organizing regions. Similar GISH patterns allowed differentiation of S. italica from S. adhaerans. However, GISH patterns did not distinguish between the genomes of S. italica and its putative wild ancestor S. viridis. GISH was also applied to polyploid Setaria species and enabled confirmation of the assumed allotetraploid nature of S. faberii and demonstration that both S. verticillata and S. verticillata var. ambigua were also allotetraploids. All these tetraploid species contained two sets of 18 chromosomes each, one from genome A and the other from genome B. Only one polyploid species, S. pumila, was shown to bear an unknown genomic composition that is not closely related either to genome A or to genome B.Key words: Setaria, genomic in situ hybridization, genome analysis.



1977 ◽  
Vol 19 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Sheng-Tian Yen ◽  
W. Gary Filion

Modified ASG (Acetic/Saline/Giemsa) and BSG (Barium hydroxide/Saline/Giemsa) chromosome banding techniques applied to several diploid species of oats produced two distinct types of C-banding patterns. One pattern consisted mainly of centromeric bands with occasional telomeric and/or intercalary bands while the other was comprised only of prominent telomeric and intercalary bands. These two banding patterns which probably reflect two distinct types of constitutive heterochromatin resulted from a change in the HCl hydrolysis temperature prior to the application of the ASG or BSG technique; hydrolysis at 60 °C yielded the centromeric bands and hydrolysis at room temperature produced telomeric and intercalary bands. Since all species examined reacted in a similar manner, precise Giemsa banding patterns should now be possible for all or most species of oats.



Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1279-1284 ◽  
Author(s):  
Rita Alicchio ◽  
Lina Aranci ◽  
Lucia Conte

We report a molecular approach to the study of the phylogenetic relationships of Avena diploid and polyploid species based on RFLP detected with three cDNA probes of nuclear genes belonging to multigenic families (low pI α-amylase, avenin, and globulin). All the probes were highly informative in the detection of polymorphism between oat species. Associations between species were determined from cluster (UPGMA) analysis based on distance values calculated from RFLP data separately for each of the two levels of ploidy. Results were in general agreement with morphology based phylogenetic analyses, confirming the large differentiation among A and C genomes in the evolution of diploid species and the genetic homogeneity among A. brevis, A. strigosa, and A. nuda and the recently discovered A. atlantica. A certain divergence was observed between two endemic species (A. canariensis and A. damascena) and the other diploid species with the A genome. The analysis of tetraploid species relationships confirms the differentiation of the barbata complex (A. wiestii, A. barbata, A. abyssinica, and A. vaviloviana) from the maroccana–murphyi–agadiriana group, which, despite some similarities in morphological and biochemical traits, seems to have accumulated deep genetic differences along its evolutionary pathway.Key words: Avena genomes, genetic distance, ploidy, RFLP, multigenic families.



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