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Understanding the evolution of floral morphology requires information about the identity of pollinators as well as the specific mechanisms of pollen transfer. Based on preliminary field observations and floral structure, we hypothesized that pollination mechanisms involving the transfer of pollen on butterfly wings occur in several lineages of South African Amaryllidaceae. Here we report findings from a detailed study of butterfly-wing pollination in two subspecies of Scadoxus multiflorus and review the prevalence of this pollination mechanism among other Amaryllidaceae in southern Africa. We established that S. multiflorus subsp. katherinae is genetically self-incompatible and thus entirely reliant on pollinators for seed production. We determined that this subspecies is pollinated almost exclusively by large swallowtail butterflies, principally males of the mocker swallowtail Papilio dardanus cenea. Flowers of S. multiflorus subsp. multiflorus are pollinated by pierid and swallowtail butterflies. Pollen is deposited on the ventral surface of the wings of butterflies as they flutter over the strongly exserted stamens. We predict that butterfly-wing pollination occurs in at least nine species of South African Amaryllidaceae, which may reflect several independent origins of this mechanism. The flowers of these species are red or orange with strong herkogamy and are either bowl-brush or open-brush in shape. We provide maps of the distribution of pollen on the ventral surface of the wings of pollinators for four of these species. All four appear to be pollinated via the ventral surface of large butterfly wings, with the floral structure facilitating the process. These findings illustrate the importance of investigating pollen transfer mechanisms in order to understand patterns of floral diversification and floral convergence.

Scadoxus multiflorus Martyn, 1795 is an ornamental plant with brilliantly colored flowers. Even though its chromosomes are rather large, there is no karyotype description reported so far. Therefore, conventional and molecular cytogenetic studies including fluorescence in situ hybridization (FISH) with 45S and 5S rDNA, and human telomere sequence (TTAGGG)n probes (Arabidopsis-type telomere probes yielded negative results) were carried out. The chromosome number is as reported previously, 2n = 18. The nine chromosome pairs include two large submetacentric, five large acrocentric, one medium acrocentric, two small metacentric and eight small submetacentric chromosomes. Hybridization sites of the 45S rDNA signals were on the short arm ends of chromosomes #1, #3 and #8, while 5S rDNA signals appeared on the long arm of chromosome 3, in one homologue as a double signal. The telomere signals were restricted to all chromosome ends. Three chromosome pairs could be newly identified, chromosome pair 3 by 5S rDNA and chromosomes #1, #3 and #8 by 45S rDNA loci. In addition to new information about rDNA locations we show that the ends of Scadoxus multiflorus chromosomes harbor human instead of Arabidopsis-type telomere sequences. Overall, the Scadoxus multiflorus karyotype presents chromosomal heteromorphy concerning size, shape and 45S and 5S rDNA positioning. As Scadoxus Rafinesque, 1838 and related species are poorly studied on chromosomal level the here presented data is important for better understanding of evolution in Amaryllidaceae.

Using sequences from the plastid trnL-F region and nrDNA ITS, we investigated the phylogeny of the fleshy-fruited African tribe Haemantheae of the Amaryllidaceae across 19 species representing all genera of the tribe. ITS and a combined matrix produce the most resolute and well-supported tree with parsimony analysis. Two main clades are resolved, one comprising the monophyletic rhizomatous genera Clivia and Cryptostephanus, and a larger clade that unites Haemanthus and Scadoxus as sister genera to an Apodolirion/Gethyllis subclade. One of four included Gethyllis species, G. lanuginosa, resolves as sister to Apodolirion with ITS. Relationships among the Clivia species are not in agreement with a previous published phylogeny. Biogeographic analysis using the divergence/vicariance method roots the tribe in Eastern South Africa, with several subsequent dispersals to the winter rainfall Western Cape region. Chromosomal change from an ancestral 2n=22 (characteristic of Clivia) is associated with each main clade. Reduction in number has occurred in all but Cryptostephanus, which has 2n=24 chromosomes. Increasing the sampling across all of the species in the tribe will allow a more detailed understanding of the biogeographic patterns inherent in the parsimony topology, which undoubtedly reflect Quaternary climatic changes in Southern Africa.

Chromosome analysis of nine species ofHaemanthus (2n = 16) and four species ofScadoxus (2n = 18), using conventional stains, Quinacrine fluorescence and C-banding, has shown that the two genera do not possess significant amounts of constitutive heterochromatin. The two genera are closely related and differ in respect of a translocation which has resulted in the dysploid reduction in chromosome number from 2n = 18 inScadoxus to 2n = 16 inHaemanthus.

We present phylogenetic analyses of 37 taxa of Amaryllidaceae, tribe Haemantheae and Amaryllis belladonna L. as an outgroup, in order to provide a phylogenetic framework for the selection of candidate plants for lead discoveries in relation to Alzheimer's disease and depression. DNA sequences from the nuclear ribosomal internal transcribed spacer (ITS) and the plastid trnL-F regions were used. Maximum parsimony analyses provide increased support for the sister relationship of Haemanthus and Scadoxus. Within Haemanthus, a well supported clade (89% BS) corresponds to a summer rainfall group (mainly Eastern Cape) with white-pale pink flowers. A second strongly supported clade (100% BS) corresponds to a winter rainfall group (mainly Western Cape) with red-pale pink flowers. Haemanthus montanus, which is from the summer rainfall region, is sister to the winter rainfall group. Alkaloid profiles and bioactivity profiles were investigated for 16 taxa using gas chromatography-mass spectrometry (GC–MS) and assays measuring acetylcholinesterase (AChE) inhibition and affinity to the serotonin reuptake transport protein (SERT). No alkaloids were detected by GC–MS in extracts of the two species of Gethyllis included in the present study suggesting that Gethyllis (and possibly Apodolirion) species may not produce the alkaloids characteristic for the family. AChE inhibitory activity was found in all investigated clades except the Apodolirion–Gethyllis clade, which can be explained by the apparent lack of alkaloids in this clade. In spite of infra-specific variability of alkaloid profiles observed, dose-dependent SERT activity appears to be pronounced and restricted to the genus Haemanthus within tribe Haemantheae. Three of eight Haemanthus species tested had IC50