Flora Zambesiaca

Taxon Detail

FZ volume:9 part:5 (2001) Euphorbiaceae by S. Carter & L.C. Leach

(Search other Kew databases for: Synadenium)

Synadenium Boiss. Key

in de Candolle, Prodr. 15, 2: 187 (1862). —N.E. Brown in F.T.A. 6, 1: 462 (1911). —S. Carter in F.T.E.A., Euphorbiaceae, part 2: 534 (1988). —Radcliffe-Smith, Gen. Euphorbiacearum: 417 (2001).

Range:

A genus confined to east and southern tropical Africa, with 14 closely related species, of which 7 occur in the Flora Zambesiaca area.

Description:

Shrubs or trees with copious caustic milky latex, monoecious.Branches cylindrical, ± fleshy and marked with large elliptic leaf scars.Leaves fleshy, with stipules modified as small but ± conspicuous dark brown glands.Inflorescence with sessile cyathia in dichotomously branching axillary cymes, usually crowded into pseudo-umbels (pseudumbels) at the branch tips; bracts paired, persistent.Cyathia with numerous male flowers in 5 groups surrounding a solitary female flower and all enclosed within a cup-like involucre.Involucres with an entire or occasionally notched spreading furrowed glandular rim surrounding 5 fringed lobes.Male flowers in 5 groups, with stamens shortly exserted from the involucre, bracteoles included.Female flower shortly pedicellate, the pedicel elongating slightly in fruit; perianth reduced to a 3-lobed rim below the ovary; styles 3, joined at the base, with bifid stigmas.Capsule 3-lobed, dehiscent.Seeds with a sessile, often rudimentary caruncle.

Notes:

Differences between the species, at least from herbarium specimens, appear to be slight, and have usually been based upon leaf and cyme-branching characters.However, emphasis should also be placed upon habit, shape and size of the cyathium, colour and furrowing of the involucral glands, and features of the capsules and seeds.Relatively little fruiting material has been collected and details are missing for the majority of species in the Flora Zambesiaca area.