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

Albers, Focke; Walt, J.J.A. van der

doi:10.1007/bf00989382

Cited by 38 publications

(17 citation statements)

References 8 publications

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“…(1999b). In summary, the small chromosome clade (clade A + B) comprises approximately 80% of the total 280 species currently described, mostly with chromosomes <1.5 µm in length (Albers & van der Walt, 1984;Gibby & Westfold, 1986;Gibby, 1990).…”

Section: Discussionmentioning

confidence: 99%

“…The remainder of the genus comprises approximately 55 species with chromosomes of 1.5-3.0 µm long (Albers & van der Walt, 1984;Gibby & Westfold, 1986;Gibby, 1990) and includes woody and succulent (sub)shrubs as well as herbaceous annuals. In a previous study (Bakker & al., 2000b) we reported an overall phylogenetic hypothesis for Pelargonium (28 species) based on cpDNA trnL-F and mtDNA nad1 gene sequences.…”

Section: Introductionmentioning

confidence: 99%

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Phylogeny of Pelargonium (Geraniaceae) Based on DNA Sequences from Three Genomes

Bakker¹,

Culham²,

Hettiarachi³

et al. 2004

Taxon

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phylogeny of Pelargonium (Geraniaceae) Based on DNA Sequences from Three Genomes

Bakker¹,

Culham²,

Hettiarachi³

et al. 2004

Taxon

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“…The rbcL sequence comparisons have provided strong evidence that Pelargonium is a monophyletic group which comprises a basal sister-group to the other four genera in the family (Price and Palmer 1993). The genus Pelargonium contains approximately 250 species (Albers, Gibby, and Austmann 1992), of which 80% are generally restricted to the winter rainfall region of the southwest coast of South Africa, particularly the Cape Province area (van der Walt and Vorster 1988). At least 30 species are restricted to areas outside of South Africa.…”

Section: Introductionmentioning

confidence: 99%

“…Thirteen sections were recognized in the genus in the provisional treatment of van der Walt (1990), and the additional section Reniformia was delimited by Dreyer et al (1992). Recent comparative studies of morphology, cytology, secondary product chemistry, and rbcL sequences conducted in a collaborative effort by anumber of research groups in South Africa, Europe, and the United States have resulted in a number of proposed changes in the sectional classification of the genus, particularly with respect to the delimitation of the highly unnatural section Ligularia (see for example Albers et al 1992;van der Walt et al 1995).…”

Section: Introductionmentioning

confidence: 99%

“…Of these, our preliminary ITS comparisons only provide support for section Hoarea as a clear-cut monophyletic group, supported by a bootstrap value of 92%. Section Ligularia has traditionally been delimited in a very broad sense, including a very heterogeneous group of species in terms of morphology and cytology (see Albers et al 1992). It is currently being divided into a number of new sections (see Albers et al 1995;van der Walt et al 1995).…”

Section: Introductionmentioning

confidence: 99%

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Diversity and Evolution of Seedling Baupläne in Perlargonium (Geraniaceae)

Jones¹,

Price²

1995

aliso

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The genus Pelargonium (Geraniaceae) exhibits tremendous variation in growth form. We apply a broadly defined concept of Bauplan in our study of growth form, architectural and anatomical features of early seedling development in the type subgenus. We analyze variation in these features within a phylogenetic framework based on sequence comparisons of internal transcribed spacer regions (ITS) of nuclear ribosomal DNA.Preliminary ITS sequence comparisons show strong support for two major clades. One major clade contains two subgroups, one consisting of three previously recognized sections of more or less woody shrubs and subshrubs (sections Pelargonium, Glaucophyllum and Campylia), and a second clade of five sections consisting of geophytes and branched stem-succulents (sections Hoarea, Ugularia, Polyactium, Cortusina and Otidia). The shrubby subgroup is characterized by relatively high levels of variation in architectural determinants such as internode elongation and branching. All members of this subgroup exhibit similar patterns of tissue production by the vascular cambium wherein secondary xylem consists predominantly of lignified tracheary elements and fibers. The stem-succulent clade shows less variation in some architectural determinants such as internode length and branching. The location of the initial onset of axis thickening is variable among species. In all sections except Ligularia, axis thickening is correlated with the onset of cambial activity wherein both secondary xylein and phloem are composed of few conducting cells scattered among abundant storage parenchyma. Section Ligularia is characterized by cambial activity similar to that in the shrubby clade; epicotylar thickening in this section arises through expansion and division of cortical cells.The second major clade within the type subgenus contains the monotypic section Isopetalum, and sections Peristera and Reniformia. Members of these sections range from shrubs that are woody at the base to herbaceous scramblers. Species examined exhibit variation in branching but limited internodal elongation. These seedlings were thin stemmed and showed relatively limited activity of a vascular cambium, which produced secondary xylem consisting of lignified tracheary elements and fibers. The occurrence of a vascular cambium producing largely lignified tracheary elements and fibers in all members of the subgenus except the stem-succulent clade suggests that this type of secondary xylem is basal within the subgenus, and that section Ligularia has either retained or reevolved the basal state.

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