Can and do ericas self pollinate

Abstract

Within the Cape Floristic Region many lineages are characterised by large floral

diversity. The genus Erica is one of these lineages, making up -7% of the CFR.

Surprisingly, even though pollinators have been suggested to be a driving force of floral

morphology, the role of pollinators in the floral diversification and speciation of this

genus is not yet well understood. Therefore the aim of this paper was to establish if

Erica species can and do self-pollinate. Two Erica species, E. plukenetii and E. urna

viridis, were obtained from Kirstenbosch nursery, where hand-pollinations were

performed on 15-20 flowers of each of three treatments (self-pollination, cross

pollination and autogamous self-pollination. Additionally pollen tube analyses were

performed on seven Erica species, which were collected from the Constantia Mountain.

In E. plukenetii, self-incompatibility seems to be the predominant breeding system. It

appears that, like E. urna-viridis, most of the other species analysed, via pollen tube

analyses, have the potential to self-pollinate. However, more experiments are required

to establish if these species are truly self-compatible. Autogamy, on the other hand, does

not appear to set seed in the species studied. Therefore it would be fair to say that some

ericas can self-pollinate but none actually do self-pollinate. These results indicate that

ericas have a strong dependence on pollinators for seed set and in the past speciation

may have occurred due to adaptation to different pollinators, when opllinators were

scarce.

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