The Genera of Leguminosae-Caesalpinioideae and Swartzieae
Habit and leaf form. Trees; without tendrils; unarmed. Phyllotaxy spiral. Leaves compound; bifoliate; paripinnate. Venation palmate, parallel or fan-like. Leaflets few per leaf (two); opposite or sub-opposite; with a strong, continuous marginal nerve (the margins crenate); sessile to sub-sessile. Stipules absent or early caducous or very inconspicuous; neither leafy nor spinescent. Stipels absent.
Inflorescence and floral morphology. Flowers small; hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx, in the corolla, and in the androecium; in simple racemes, or in panicles; not distichous. Bracts absent at anthesis (caducous, minute). Bracteoles absent; absent at anthesis. Hypanthium absent. Calyx polysepalous; more or less regular; 4 partite; imbricate. Corolla absent. Disk absent (or small). Androecium of more than ten parts; members all free of one another; members all more or less equal in length; without staminodia. Fertile stamens 20–25. Anthers attached well above base of connective. Dehiscence lateral. Ovary stipitate. Stigma peltate. Ovules solitary.
Fruit, seed and seedling. Fruit a follicle, or indehiscent; not becoming woody; without prominent raised veins; not winged; without markedly twisting or enrolling valves. Seeds not arillate; with a straight or slightly oblique radicle; amyloid-negative. Cotyledons not flat; of Type 2; epigeal.
Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll. Mesophyll secretory cavities (gland-dots) common; epithelium-lined. Adaxial hypodermis absent. Leaf girders absent. Laminae isobilateral, with adaxial and abaxial palisades. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.
Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs not seen. No compound or branched eglandular hairs seen. Capitate glands not seen. Expanded and embedded hair-feet absent. Adaxial interveinal epidermal cell walls straight in optical section; not conspicuously pitted; thin. Stomata adaxially common and widespread. Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; not conspicuously pitted in optical section; staining normally with safranin; thin.
Pollen ultrastructure. Tectum reticulate; finely to moderately regularly reticulate. Length of colpi inapplicable grain periporate.
Cytology, geography, etc. Basic chromosome number, x = 17 and 18. 2n = 36. 1 species. Southern tropical Africa. Not widely cultivated.
The interactive key provides access to the character list, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, and summaries of attributes within groups of taxa.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, identification, and information retrieval. In English and French; French translation by E. Chenin. Version: 22nd March 2009. http://delta-intkey.com’.