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.

Breeding systems of plants determine their reliance on pollinators and ability to produce seeds following self-pollination. Self-sterility, where ovules that are penetrated by self-pollen tubes that do not develop into seeds, is usually considered to represent either a system of late-acting self-incompatibility or strong early inbreeding depression. Importantly, it can lead to impaired female function through ovule or seed discounting when stigmas receive mixtures of self and cross pollen, unless cross pollen is able to reach the ovary ahead of self pollen ('prepotency'). Self-sterility associated with ovule penetration by self-pollen tubes appears to be widespread among the Amaryllidaceae.• We tested for self-sterility in three Cyrtanthus species -C. contractus, C. ventricosus and C. mackeniiby means of controlled hand-pollination experiments. To determine the growth rates and frequency of ovule penetration by self-versus cross-pollen tubes, we used fluorescence microscopy to examine flowers of C. contractus harvested 24, 48 and 72 h after pollination, in conjunction with a novel method of processing these images digitally. To test the potential for ovule discounting (loss of cross-fertilisation opportunities when ovules are disabled by self-pollination), we pollinated flowers of C. contractus and C. mackenii with mixtures of self and cross pollen.• We recorded full self-sterility for C. contractus and C. ventricosus, and partial selfsterility for C. mackenii. In C. contractus, we found no differences in the growth rates of self-and cross-pollen tubes, nor in the proportions of ovules penetrated by selfand cross-pollen tubes. In this species, seed set was depressed (relative to cross-pollinated controls) when flowers received a mixture of self and cross pollen, but this was not the case for C. mackenii.• These results reveal variation in breeding systems among Cyrtanthus species and highlight the potential for gender conflict in self-sterile species in which ovules are penetrated and disabled by pollen tubes from self pollen.

Fleshy fruits are usually associated with ingestion of seeds but can also serve as a reward to animals that discard seeds without ingesting them. We investigated the seed dispersal systems of two South African Scadoxus lilies. Like those in some other genera in Amaryllidaceae tribe Haemantheae, seeds of Scadoxus are non-orthodox, reputedly poisonous and enclosed within fleshy fruits. The bright red ripe Scadoxus fruits attract monkeys, which consume the fleshy fruit and spit out the seeds. Depulping increases the rate of seed germination. Monkeys spit some seeds out in the immediate vicinity of the plant and carry others further away in their cheek pouches (84% of S. multiflorus subsp katherinae seeds and 78% of S. puniceus seeds were dispersed further than 1 m away from the parent plant). Both species occur in very specific spatially restricted habitats; S. multiflorus subspecies katherinae is confined to patches of swamp within forests, while S. puniceus is confined to small bush clumps in a grassland mosaic. Monkey-mediated seed dispersal may be advantageous for these two Scadoxus species as it ensures that some seeds are spat out in the immediate spatially restricted habitats of the parent plants, while others are carried through cheek-pouching to more distant habitat patches.

No abstract

Seed dispersal is a key process, contributing to the spread and abundance of plant species and, ultimately, the biotic diversity in communities (Cain et al., 2000;Cousens et al., 2008). The seed dispersers of plants are important for the distances of seed dispersal and the microhabitat in which seeds land, both of which influence the chances of successful recruitment (Howe & Miriti, 2004). The effectiveness of a seed disperser depends on the quality of the seeds dispersed as well as the quality of the habitat provided for each dispersed seed (Schupp, 1993). Seed dispersal kernels (the probabilities of their dispersal distances) affect abundance, diversity, and distribution, which in turn are affected by habitat structure (Levine & Murrel, 2003).Dispersal kernels need to correspond to the spatial structure of the habitat patches required for seedlings to survive and in some cases, this may actually favor short-distance dispersal (Mathius et al., 2001).Plants with seeds dispersed by frugivorous birds and monkeys are usually characterized by fleshy, brightly colored fruits