4594.010 Searsia F.A. Barkley

Trees, shrubs or suffrutices. Leaves alternate, 3-foliolate. Panicles terminal, axillary or both. Flowers unisexual, rarely bisexual, very small (calyx segments usually less than 1 mm, petals usually less than 2 mm). Male flowers: calyx (4-)5(-6)-partite; petals (4-)5(-6), white, green or yellow; stamens 5; pistillode usually 0. Female flowers: calyx and petals similar to male; staminodes frequently present; ovary usually 1-locular. Styles 3. Fruit a spherical or ovoid and flattened drupe, frequently asymmetrical. Seeds ovoid or reniform, flattened.

Derivation of name: after Paul B. Sears, 1891-1990, who was a renowned stratigraphic palaeontologist, ecologist and head of the Yale School of Botany

Comment: Recent phylogenetic analyses of the Rhus complex using DNA and gene spacers have shown that the genus Searsia is clearly monophyletic and widely separated from Rhus sensu stricto. A further distinction is that Searsia is confined to the Old World (the Mediterranean, Africa and Asia) and Rhus sensu stricto is a New World genus.

Furthermore, with their pinnately compound leaves, drupes with prominent red glandular hairs and resinous mesocarp, the species of Rhus differ from the species of Searsia, which are characterized by ternate, rarely simple or palmate leaves and pale, glabrous or tomentose, drupes with a resinous mesocarp adhering to the bony endocarp.

Searsia is a common genus in the flora area and by no means always an easy one to name. Species of Searsia with toothed leaflets can easily be confused with species of Allophylus. See note 3 for a discussion of the differences.

Worldwide: c. 110 species in the Old World, specifically the Mediterranean, Africa and Asia

Botswana: 15 taxa.