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.     

A cytological study ofPelargonium sect.Eumorpha (Geraniaceae)

The chromosome numbers of seven species ofPelargonium sect.Eumorpha have been determined from material of known wild origin, and karyotypic comparisons have been made. Within the section there is variation in basic chromosome number (x = 4, 8, 9, 11), variation in chromosome size, and two species have polyploid races. The three species with chromosome numbers based on x = 11 have the smallest chromosomes (1.0–1.5 µm); chromosomes are larger (1.0–3.0 µm) in the other species.P. elongatum has the lowest chromosome number in the genus (2n = 8).P. alchemilloides is exceptional in that it has four cytotypes, 2n = 16, 18, 34 and 36, and the form with 2n = 36 has large chromosomes (2.0–5.0 µm). Evidence from a synthesized hybrid suggests thatP. alchemilloides with 2n = 16 may be of polyploid origin. The three species based on x = 11 appear to be more closely related to species from other sections ofPelargonium that have the same basic chromosome number and small chromosome size, rather than to other species of sect.Eumorpha.     

A further note on the relationships of the EuropeanLinum hologynum and the Australian species ofLinum (Linaceae)

The diploid chromosome number for the EuropeanLinum hologynum and the haploid number for the AustralianL. monogynum is 42 and appears to establish a new and distinctive base number for sect.Linum. The possession by these two species and by the AustralianL. marginale of multiporate pollen and united styles, a unique combination of features in sect.Linum, may warrant the establishment of a new subsection in that section to accommodate the three species.     

Die Chromosomenzahlen der in Mitteleuropa vorkommenden Arten vonOrobanche sect.Orobanche

The chromosome numbers of five species ofOrobanche sect.Orobanche (O. alsatica, O. laserpitii-sileris, O. loricata, O. salviae, O. teucrii) are reported for the first time and previous counts could be verified in ten other species. Now the chromosome numbers of all species of sect.Orobanche occurring in Central Europe are known: they are diploid (2n = 38) with the exception ofO. gracilis (tetra- and hexaploid, aneusomatic).

     

Stelar structure ofAsplenium obtusifolium and its allied species in the New World tropics,with comparison to the Asian members ofAsplenium sect.Hymenasplenium

The stelar structure ofAsplenium obtusifolium and its related species (A. repandulum, A. riparium, A. triquetrum, A. volubile, A. purpurascens, A. ortegae, A. delitescens, A. hoffmannii, andA. laetum) in the New World tropics was observed and compared to that of Asian species ofAsplenium sect.Hymenasplenium. Both of the groups were found to share peculiar stelar structures: steles with two meristeles, a broader ventral and a narrower dorsal, each providing one of the two leaf traces; leaf gaps arranged in two rows between the dorsal and ventral strands, which are connected by thin meristeles, delimiting the leaf gaps. These structures are distinct from the radial symmetrical ones general inAsplenium. Together with cytological evidence, this strongly indicates that the New and Old World groups are closely related. Thus, these Neotropical species should be included in sect.Hymenasplenium.     

Karyological studies onGentiana sect.Chondrophyllae (Gentianaceae) from China

Nineteen populations of fifteen species ofGentiana sect.Chondrophyllae from China were observed cytologically.Gentiana alsinoides, G. anisostemon, G. asterocalyx, G. exigua, G. heterostemon, G. intricata, G. praticola, G. pseudoaquatica, G. spathulifolia, andG. subintricata all had the same chromosome number of 2n = 20 (or n = 10), whereasG. piasezkii had 2n = 36,G. squarrosa 2n = 38,G. prattii 2n = 18,G. aristata 2n = 14 (n = 7), andG. heleonastes 2n = 12. All these chromosome numbers are documented here for the first time, except forG. squarrosa, where it is a new number report. The basic numbers of x = 6, x = 7 and x = 19 are new for the section. Karyotype analyses of some species revealed that, except for a few cases, the species examined mainly had metacentric chromosomes. 2n = 20 = 2m(SAT) + 18m was found to be the main type of karyotype for the species with 2n = 20. Chromosomal evolution and its mechanism in this section are also discussed.     

Delimitation ofPelargonium sect.Glaucophyllum (Geraniaceae)

Pelargonium otaviense Knuth andP. spinosum Willd. are excluded from sect.Glaucophyllum, whileP. grandiflorum (Andr.)Willd.,P. patulum Jacq. andP. tabulare (Burm. f.)L'Hérit. of sect.Eumorpha are included. Sect.Glaucophyllum is characterized by green to glaucous vegetative organs and zygomorphic white to pink corolla with five narrow petals. All the species have an identical pollen and chromosome morphology, the same basic chromosome number (x = 11) and similar flavonoid patterns. A close relationship between sect.Glaucophyllum and sect.Pelargonium is indicated by the occurrence of natural hybrids and concordant characters. Isorhamnetin and luteolin have been detected in the genus for the first time.     

A review of chromosome cytology in Hyacinthaceae subfamily Ornithogaloideae (Albuca, Dipcadi, Ornithogalum and Pseudogaltonia) in sub-Saharan Africa

The chromosome cytology of Hyacinthaceae subfamily Ornithogaloideae is reviewed within the framework of a recent molecular-based classification, with particular emphasis on its center of diversity in sub-Saharan Africa. We also provide new chromosome counts for sections that are unknown or poorly known cytologically. Albuca subgen. Namibiogalum (9 spp.) probably has an ancestral base number of x = 10 but subgen. Albuca (± 70 spp), subgen. Monarchos (9 spp.) and subgen. Osmyne (36 spp.) have x = 9. The pattern in subgen. Urophyllon (3 spp.) is remarkable: although x = 6 is likely, the species in the section exhibit a range of 2n = 12, 10, 8, 6 and 4 (exclusive of polyploidy). All karyotypes have three large chromosome pairs and a variable number of small chromosomes. Pseudogaltonia (2 spp.) has x = 9 and Dipcadi (26 spp.) possibly x = 9 in series Uropetalum and x = 6 in series Dipcadi, which exhibits a pattern of descending dysploidy leading to n = 3 in D. marlothii. In Ornithogalum (± 130 spp.) chromosome numbers are known for only 24 of the ± 84 sub-Saharan species, mostly from subgen. Aspasia and subgen. Ornithogalum sect. Linaspasia, both of which have x = 6, and from subgen. Galtonia, which has x = 8. In contrast, x = 7 is basic for the Eurasian sects. Honorius and Melophis, and x = 18 seems likely for sect. Cathissa. Sect. Ornithogalum, the cytology of which we does not examine in detail, may have x = 9. Polyploidy is apparently rare in the sub-Saharan African ornithogaloids, in marked contrast to the high frequency of polyploidy among Eurasian species. In Albuca just 3 or possibly 4 sub-Saharan species (9% or 13% of those counted) are exclusively polyploid and 5 more have diploid and polyploid races; and in sub-Saharan Ornithogalum, only the tropical O. gracillimum is exclusively polyploid, and the western southern African O. hispidum has diploid and polyploid races.     

Karyological studies inPelargonium sectt.Ciconium,Dibrachya, andJenkinsonia (Geraniaceae)

Pelargonium sect.Ciconium and sect.Dibrachya have a basic chromosome number of x = 9, whereas sect.Jenkinsonia has x = 9, 11, and 17.     

Karyological notes onCentaurea sect.Acrocentron (Asteraceae)

The karyology ofCentaurea sect.Acrocentron is surveyed. 19 chromosome counts on 8 species are reported; those onC. acaulis, C. crocata, C. galianoi, C. pubescens, andC. malinvaldiana are new. The basic chromosome numbers of the section are x = 11 and x = 10. Karyological arguments have been used to show that evolution was from x = 11 to x = 10. This is supported by biogeographical data. Two main centres of diversification of sect.Acrocentron were studied from that point of view: the East and the Southwest Mediterranean region.     

Pelargonium caroli-henrici (Geraniaceae), a new species from the Western Cape Province

Pelargonium caroli-henrici spec. nova (sect.Hoarea) is described. The new species is apparently endemic to quartzite areas of Vanrhynsdorp Division in the western Cape Province (South Africa). The chromosome number 2n = 22 was counted on specimens in cultivation.Dedicated to Prof.K. H. Rechinger on the occasion of his 80th birthday.     

Evolution alpiner Populationen vonEuphrasia (Scrophulariaceae): Chromosomenzählungen an diploiden und polyploiden Sippen aus den Ostalpen

Chromosome counts are reported for several E. Alpine taxa ofEuphrasia sect.Euphrasia. First records of diploidy for small-flowered taxa are 2n = 22 forE. inopinata andE. sinuata, related toE. minima (4 x). Aberrant E. AlpineE. hirtella is 2 x, just as the typical W. Alpine populations of this species. Tetraploidy, 2n = 44, has been found inE. pumila, close toE. stricta (also 4 x). The limitation of ploidy levels within sect.Euphrasia to 2 x and 4 x on the chromosome base number x = 11 is confirmed.

     

Untersuchungen zur Karyologie und Mikrosporogenese vonPelargonium sect.Pelargonium (Geraniaceae)

The chromosome numbers of the 24 species of sect.Pelargonium were determined from field collected and cultivated plants of known localities in S. Africa. Twelve species are diploid (2n = 22), eight tetraploid (2n = 44), one hexaploid (2n = 66), and three octoploid (2n = 88). The chromosome numbers correlate well with the proposed subdivision of sect.Pelargonium. Its chromosomes are relatively small (1.0–1.5 µm) in comparison to most of the other sections, and its diploid karyotype is considered to be primitive. The occurrence of the basic number x = 11 in this section, in other sections of the genus, and in related genera (Monsonia, Sarcocaulon) leads to the conclusion that x = 11 probably is basic for the whole genus. — The pollen meiosis, microsporogenesis and pollen fertility of the diploid species is normal, with the exception of one, possibly young taxon from the Greyton Nature Reserve. The tetraploid species could be of autoploid origin, the higher polyploids exhibit a mixed auto-alloploid nature. — The 20 diploid and tetraploid species have a relatively small distribution range, most of them occur in the SW. Cape Province of South Africa. This area may therefore be considered as the centre of origin of the genus. Three of the four high polyploid species occupy rather large areas.

Untersuchungen zur Karyologie und Mikrosporogenese der GattungPelargonium, 1.     

Chromosomal evolution ofGentiana andJaeschkea (Gentianaceae), with further documentation of chromosome data for 35 species from western China

Chromosome numbers were recorded for 63 populations of 34 species belonging to the genusGentiana from the high altitude regions of western China. Counts for 22 species were reported for the first time and new numbers were found forG. heleonastes (2n = 36),G. prattii (2n = 20) andG. pseudoaquatica (2n = 40). Incorporating previous data, a complete series of gametic chromosome numbers from n = 6 to 24 and 26 was established for the genus, suggesting rapid karyotypic evolution by a combination of dysploidy and polyploidy. The cytotype 2n = 20 is proposed as the ancestral type in sect.Chondrophyllae s. l. The chromosome number 2n = 16 was found forJaeschkea microsperma for the first time which, with previous reports of 2n = 18, 20 and 22, indicates thatJaeschkea is a typically dysploid genus.     

Chloroplast DNA variation and the phylogeny ofAsplenium sect.Hymenasplenium (Aspleniaceae) in the New World tropics

Asplenium sect.Hymenasplenium is a well-defined group in Aspleniaceae, distinguished by several morphological and cytological characters. However, interspecific relationships in the section were not clear. In this paper, we report the phylogenetic relationships of 9 Neotropical species of sect.Hymenasplenium determined by chloroplast DNA restriction site variation analyses. From the obtained phylogenetic tree, two major clades: one withA. obtusifolium, A. riparium, A. volubile andA. repandulum and another withA. delitescens, A. ortegae, A. purpurascens, A. laetum andA. hoffmannii were recognized.Asplenium delitescens was shown to have a polyphyletic origin. It was also shown that the epiphytic habit evolved only once in the New World species of sect.Hymenasplenium.     

Molecular phylogeny ofIva (Asteraceae,Heliantheae) based on chloroplast DNA restriction site variation

Iva s.str. (comprising ten species) was examined by cpDNA restriction site variation to determine phyletic relationships within the group. The results were compared with relationships proposed from other data. A total of 86 restriction site mutations was detected, 47 of which proved phylogenetically informative. A single most parsimonious tree was obtained using both Wagner and Dollo parsimony. The tree revealed three main lineages that are congruent with the three chromosome lineages (base numbers of x = 16, 17, 18). The monophyly of the x = 16 and 18 groups was supported strongly by molecular data, while the monophyly of x = 17 lineage was only supported moderately. Relationships among the three lineages indicate that the sect.Iva is paraphyletic because sect.Linearbractea is nested within it. Both morphological data and the secondary chemical data are in agreement with the proposed cpDNA phylogeny. Because of this agreement, sect.Iva is revised such that,I. axillaris was excluded and positioned within the newly proposed sect.Rhizoma. Patterns and rates of cpDNA evolution were also examined. The results indicated an uneven evolution in the chloroplast genome with different rates of cpDNA evolution in at least a few species ofIva. However, the evolutionary clock hypothesis can not be rejected within most of the lineages inIva.     

Centaurea tchihatcheffii Fischer & C.A. Meyer (Asteraceae)

Centaurea tchihatcheffii is a steppic annual possessing some unique features absent in other Centaureas. The chromosome number is 2n = 20, differing from all other annual species of Centaurea sect. Cyanus. The type locality as published is erroneous and the correct provenance is provided.     

凤仙花近缘种间核型分析与叶表皮微形态研究

为探究凤仙花近缘种植物的细胞学和微形态学方面的亲缘关系,该文选取荔波凤仙花(Impatiens liboensis)及近缘种赤水凤仙花(I.chishuiensis)和管茎凤仙花(I.tubulosa)的根尖和叶表皮为实验材料,采用体细胞染色体常规压片法和叶表皮光学显微镜观察法对凤仙花近缘种植物进行染色体及叶表皮特征研...     

A survey of C-band patterns in chromosomes ofLilium (Liliaceae)

C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.Dedicated to Prof.D. G. Catcheside on the 80th anniversary of his birth.     

A reappraisal ofPelargonium sect.Ligularia (Geraniaceae)

A study of 33 species ofPelargonium sect.Ligularia reveals four basic chromosome numbers, x = 8, 9, 10, and 11, and variation in chromosome size. From evidence of karyology and hybridization attempts, proposals are made to divide the section into smaller groups and to transfer some species to other sections.