Karyotypes in Leucadendron (Proteaceae): evidence of the primitiveness of the genus.

Karyotypes of 27 species in Leucadendron are analysed for the first time. New chromosome counts are reported for 15 species, with 2 n = 26 occurring in all of them. Karyotype analysis indicated that chromosomes of Leucadendron taxa are small in size and have predominantly median to submedian centromeres. The mean sizes of somatic metaphase chromosomes ranged from 1.05 to 2.65 µm. Based on Stebbins’ karyotype classification, 1A type was found in L. galpinii, L. muirii, L. orientale, L. platyspermum, L. rubrum, and L. salignum; 2A type in L. conicum, L. flexuosum, L. laureolum, L. meridianum, L. salicifolium, L. stelligerum, and L. teretifolium; and 2B type in L. argenteum, L. chamelaea, L. discolor, L. elimense, L. eucalyptifolium, L. floridum, L. gandogeri, L. linifolium, L. loeriense, L. macowanii, L. procerum, L. spissifolium, L. strobilinum, and L. tinctum. These types are the three most symmetrical karyotypes and are considered to be primitive. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 387–394. [ABSTRACT FROM AUTHOR]