IBONE   05434
INSTITUTO DE BOTANICA DEL NORDESTE
Unidad Ejecutora - UE
artículos
Título:
Natural hybridisation in Andropogon and its impact on taxonomic literature
Autor/es:
NORRMANN, GUILLERMO
Revista:
BOTANICAL JOURNAL OF THE LINNEAN SOCIETY
Referencias:
Año: 2007
ISSN:
0024-4074
Resumen:
In north-eastern Argentina, Paraguay and SE Brasil, morphologically intermediateplants involving Andropogon lateralis, A. bicornis, A. glaziovii, A. arenarius and A.hypogynus were found. The possibility that they were natural hybrids was tested in twoways: (i) where they were sterile, their morphology was compared with that of the putativeparents and their meiosis and reproductive behaviour were studied; (ii) wherethey were fertile, studies of artificial hybrids were also made. Most of the hybrids aresterile. The only fully fertile combination, generating recombination and hybridswarms, is A. lateralis × A. hypogynus. In spite of apparently normal chromosomepairing, fertility was low in all other combinations, both on the male and the femaleside. Sterility is probably due to ‘cryptic’ or ‘gametic sterility’, which produces completesterility of the gametes. Many of the hybrids survive and compete successfullywith the parental species in natural populations, but their sterility maintains the geneticisolation of the majority of the taxa involved. Meiotic chromosome behaviour in all thehybrids indicates that the group of species share slightly different forms of three basicgenomes. Several specimens of natural hybrids were found in classic herbarium collections.In the past, they were given the status of type specimens of at least five taxonomicentities (A. lindmanii, A. coloratus, A. lateralis var. subtilior, A. multiflorus andA. lateralis var. bogotensis). The taxonomic consequences of these findings are discussed.© 200x The Linnean Society of London, Botanical Journal of the LinneanSociety, 200x, xxx, xxx.