Chromosome numbers in Malawian Commelinaceae

In this account chromosome numbers of 22 species and varieties from five genera of Commelinaceae occurring in Malawi are given. For 14 of them this is the first time their chromosome numbers have been reported. A wide range of chromosome numbers of 2n = 26 , 28, 30. 44. 52 and 60 is noted in Commelina.     

Cytological variation and evolution withinPelargonium sectionHoarea (Geraniaceae)

Chromosome numbers of 65 species of sect.Hoarea have been determined. These show three basic chromosome numbers, x = 11, 10 and 9. Only a few species are tetraploid. In five species both diploid and tetraploid cytotypes are reported. Several cases of deviations in chromosome numbers and cytological abnormalities were found, most of these being related to the presence of B chromosomes that occur in eight species. Evidence is presented to suggest that the basic chromosome numbers of x = 10 and x = 9 are derived from x = 11 by centric fusion. Although variation in basic chromosome number withinPelargonium has been the subject of detailed study, this is the first time that evidence has been found for a mechanism of change in basic number, that of centric fusion by Robertsonian translocation. For the species of sect.Hoarea with x = 9, where the evidence for Robertsonian translocation is greatest, this process has probably taken place quite recently. In contrast to results from other sections of the genusPelargonium, the three different basic numbers of sect.Hoarea do not contradict its delimitation as a natural taxon.     

Cytological Observation of 4 Chinese Moss Species

In this paper the chromosome countings of 4 moss species are reported for the first time in China. The materials used for investigation were taken from immature capsules. Meiosis in spore mother cells and also mitosis in the case of Plagiomnium cuspidatum were observed, with the result: Didymodon constrictus, n=14, Entodon schensianus, n=10+lm; Plagiomnium cuspidatum, n=6, Cratoncuron jilicinum, n=10. The chromosome numbers ofthe former two species are reported for the first time.     

Chromosome counts in the genusAlchemilla (Rosaceae) from SW Europe

This paper presents the results of a karyological analysis of 14 species ofAlchemilla L. collected from SW Europe (Spain and French Pyrenees). About 75% of the analyzed species have chromosome numbers 2n = 95–136. A few species have lower chromosome numbers. The chromosome numbers of 13 species are presented for the first time.     

国产香茶菜属十三个分类群的细胞学研究

对国产11种2变种共16个居群的香茶菜属植物的染色体数目进行了研究。除线纹香茶菜细花变种以外,其它种类的染色体数目均为首次报道。研究结果表明,有12个物种为二倍体,其染色体数目均为2n=24,推测该属植物的染色体基数为x=12。而细锥香茶菜既有染色体数目为2n=24的居群,也存在2n=48的居群,表明该种为二倍体或四倍体,同时2n=48的染色体数目也是香茶菜属内的首次报道。     

Chromosome numbers of miscellaneous Malagasy Acanthaceae

Meiotic chromosome numbers are reported for 12 species in eight genera of Acanthaceae from Madagascar. Chromosome numbers of 11 species are reported for the first time. Counts inMendoncia (n=19) andNeuracanthus (n=20) are the first for these genera. A new chromosome number (n=30) is reported inJusticia. Systematic implications of the chromosome counts are addressed and basic chromosome numbers for these eight genera of Malagasy Acanthaceae are discussed.     

Chromosome number of forty species of scattered bamboos

This paper reports chromosome numbers of forty species in nine genera of scattered bamboos native in or introduced to China. The chromosome numbers of 31 species are reported here for the first time.     

40种散生竹的染色体数目

报道中国9属40种散生竹类染色体数目,其中31种为首次报道。     

Does polyploidy occur in central European species of the family Sphaeriidae (Mollusca: Bivalvia)?

Some representatives of the bivalve family Sphaeriidae are assumed to be polyploid. In this study, 11 sphaeriid species (nine of the genus Pisidium, one of Musculium, and one of Sphaerium) inhabiting central Europe were studied karyologically, 10 of them for the first time. Analysis revealed high chromosome numbers (from 140 to 240). To elucidate the origin of high chromosome numbers, DNA contents were measured by flow cytometry in 5 of the studied species and, for comparison, in S. corneum and S. nucleus, which are known to be diploid (2n=30). Species with high chromosome counts yielded very similar DNA contents that are not higher than in the related species with low diploid numbers. This finding contradicts a possible origin of these species by recent polyploidization or hybridization of related species. Chromosome complements of the investigated species with high chromosome numbers differ from those with low 2n in their small chromosome size and the high proportion of subtelo- or acrocentric chromosomes. This indicates their possible origin either by an ancient polyplodization event followed by chromosomal rearrangements or by multiple chromosome fissions.     

Chromosome numbers in some Polish critical or rare Liverworts (Hepaticae)

Chromosome numbers of several hepatic species collected in Poland are published. Polymorphism in chromosome numbers was discovered in Jungermannia leiantha Grolle: most Polish populations showed n = 9 and only two n = 18; chromosome number n = 9 in Jungermannia subulata was confirmed. For Lophozia hyperborea Schust. & Dams. (n = 9) and for Lophozia kunzeana (Hüb.) Evans (n = 1*) the chromosome numbers are published for the first time.     

三种绞股蓝植物染色体观察

本文对分布于陕西省的3种绞股蓝植物进行了染色体观察。其结果：绞股蓝染色体数为2n=2x=22,长梗绞股蓝为2n=2x=22,心籽绞股蓝为2n=6x=66。后两种为本文首次报道。 这些观察结果为我国绞股蓝属植物的分类和推广利用提供了细胞学依据。     

Chromosome numbers in the genus Mimosa L.: cytotaxonomic and evolutionary implications

Chromosome numbers were determined for 125 accessions of 92 taxa of Mimosa from all five of Barneby??s (Mem New York Bot Gard 65:1?C835, 1991) taxonomic sections. For 69 species, 1 subspecies and 8 varieties, chromosome numbers are presented for the first time, for 6 species and 1 variety previously published data have been confirmed and for 3 species and 2 varieties different numbers were found. Results show that 74% of the accessions were diploid (2n?=?2x?=?26) and 26% polyploid, these mostly tetraploid (2n?=?4x?=?52) but with two triploid (2n?=?3x?=?39). These results double the number of Mimosa species for which the chromosome count is known from less than 10% previously reported to more than 20%, representing an important advance in the cytotaxonomy of this legume genus. These results together with literature data show that ca. 78% of Mimosa species are diploid. Polyploids are present in most of the taxonomic sections and in different lineages across the genus. No particular chromosome number is restricted to a given section or lineage. A possible relation between geography, species distribution, polyploidy and invasiveness was detected, however, further studies based on more accessions, especially from higher latitudes, are required before firm conclusions can be drawn.     

香港喜盐草属植物的核型分析

报道了分布于我国香港特别行政区的喜盐草属(Halophila Thou.) 2种植物的染色体数目和核型,其体细胞中期染色体数目均为2n=18。它们的核型公式分别为：喜盐草(H. ovalis (R. Br.) Hook. f.) 2n=2x=18=4m+14sm;贝克喜盐草(H. beccarii Asch) 2n=2x=18=8m+10sm(首次报道)。核型均属于2B型。     

Cytology and systematica of Araceae

The chromosome numbers of 75 species belonging to the family Araceae have been determined. The numbers for 53 species are reported for the first time. One number differs from previous reports ( Aglaodorum ), and one number is corrected (Phymatarum). Within 15 genera ( Gymnostachys, Pothoidium, Alloschemone, Heteropsis, Holochlamys, Anaphyllopsis, Dracontioides, Pseudohydrosme, Montrichardia, Bucephalandra, Taccarum, Asterostigma, Gorgonidium, Spathantheum and Ulearum ) the chromosome numbers have not previously been determined. The total number of genera cytologically investigated is now 99 (c. 94%).
A great diversity in chromosome numbers as well as in chromosome size and constitution is found. The results are discussed in relation to the phylogeny and the previously published classifications of the family.
A total list of chromosome numbers counted (>700 species) in the Araceae is presented (Appendix).     

Chromosome diversity of South American Oxalis (Oxalidaceae)

Mitotic or meiotic chromosome studies are reported for 39 species or subspecies of Oxalis from South America belonging to 14 sections. Chromosome numbers of 34 of these taxa are reported for the first time. Diploids and polyploids with six different basic chromosome numbers x=5, 6, 7, 8, 9 and 11 are described. Thirteen species of subgenus lhamnoxys were analysed and two new basic chromosome numbers were observed in diploid entities of this subgenus, x = 6 and x=9. The underground stem-bearing entities of Oxalis subgenus Oxalis studied (in sections Articulatae, Jonoxalis and Palmatifoliae) are mostly diploids and polyploids with a basic chromosome number x=7. Five species of section Carnosa are diploids with x = 9. In species of sections Rosea, Ortgieseae, Clematodes and Laxae the basic chromosome numbers x = 6, 7, 8 and 9 were observed. Groups of related species sharing the same chromosome number are discussed with the aim of improving the infrageneric delimitation of the genus. The basic chromosome number x=6 seems to be primitive in the genus and other basic chromosome numbers probably appeared several times in the course of chromosome evolution of Oxalis .     

Chromosome numbers of some caespitose bamboos native in or introduced to China

This paper reports chromosome numbers of 94 species in 13 genera of caespitose bamboos native in or introduced to China. The chromosome numbers of 74 species are roported here for the first time. The original basic number of bamboos is considered to be x = 8. Chromosome numbers ofmost of the caespitose bamboos are found to be 2n = 70 ± 2.     

Karyological studies in Hyoscyamus species of Iran

Karyological studies were performed on Hyoscyamus species of Iran. The species studied showed variation with regard to chromosome number and details of karyotype. Two different basic chromosome numbers of x=14 and 17 were recorded for the genus corresponding to the two subgenera of Hyoscyamus . Chromosome numbers of six species are reported for the first time.     

Taxonomic and evolutionary implications of intraspecific variability in chromosome numbers of species of Leucaena Benth. (Leguminosae)

Chromosome numbers were determined in 52 individuals of 14 taxa of Leucaena Benth. from 22 populations. For L. cuspidata and L. kmpirana these are the first published chromosome counts. Intraspecific variability was found for L. lempirana, L. macrophjlta and L. shanonii , and one diploid population of the tetraploid species L. pallida was identified. Comparison of our data with those in the literature showed that for L. collinsii and L. macrophylla there is a relationship between chromosome number and subspecies delimitation. The variability detected in chromosome numbers shows the complexity of the diploid and tetraploid species evolution, and suggests multiple origins for some of the polyploid taxa.