Gerrardina

Introduction

Gerrardina is a genus of two species native to southern and eastern Africa. Traditionally, the genus has been placed in the polyphyletic family Flacourtiaceae due to its gross similarities with tribe Homalieae, which have alternate, simple, toothed leaves, receptacular disk glands, and stamens opposite petals. However, Gerrardina differs from tribe Homalieae, now placed in Salicaceae, by having apical placentation, small embryos, different leaf teeth, and a mucilaginous foliar epidermis. Analyses of plastid DNA data indicate that Gerrardina is related to Brassicales, Huerteales, Malvales, and Sapindales, but further placement has not been possible given the data presently available.

Characteristics

Shrubs or small trees, sometimes scandent. Leaves simple, alternate, stipulate; venation pinnate; margins serrate. Inflorescences axillary, in few-flowered raceme-like cymes. Flowers hermaphroditic, actinomorphic, perigynous. Calyx lobes 5, persistent, aestivation imbricate. Corolla lobes 5, caducous. Stamens 5, opposite petals; anther dehiscence longitudinal, introrse. Disk present, cupular, adnate to the hypanthium. Gynoecium of 2 carpels united to form a compound, superior ovary (though recessed in the receptacle) topped by a single style with a subcapitate or minutely bifid stigma; ovary unilocular; ovules 4, anatropous, borne on 2 placentae, pendulous from near the apex. Fruits pendulous, dry or fleshy berries with 1-4 seeds. Seeds exarillate; embryo minute, erect.

Other Names for Gerrardina

• Gerrardinaceae

References

Alford, M. H. 2006. Gerrardinaceae: a new family of African flowering plants unresolved among Brassicales, Huerteales, Malvales, and Sapindales. Taxon 55: 959-964.

Killick, D. J. B. 1976. Flacourtiaceae. Pp. 53-92 in J. H. Ross, ed. Flora of South Africa. Vol. 22. Botanical Research Institute, Pretoria.

Milne-Redhead, E. 1939. Gerrardina eylesiana Milne-Redhead. Hooker's Icon. Pl., Fifth Series 4: 1-2, t. 3390.

Oliver, D. 1870. Gerrardina foliosa, Oliv. Hooker's Icon. Pl., Third Series 1: 60. t. 1075.

Sleumer, H. O. 1975. Flacourtiaceae. In R. M. Polhill, ed. Flora of Tropical East Africa. Crown Agents for Oversea Governments and Administrations, London.