The Genera of Leguminosae-Caesalpinioideae and Swartzieae
Habit and leaf form. Trees; without tendrils; unarmed. Phyllotaxy distichous, or spiral. Leaves compound; pinnate; paripinnate. Leaflets many per leaf, or few per leaf; opposite or sub-opposite; without a continuous marginal nerve; petiolulate, or sessile to sub-sessile; with petiolules not noticeably twisted. Stipules absent or early caducous or very inconspicuous; connate (intrapetiolar). Stipels absent.
Inflorescence and floral morphology. Flowers hermaphrodite, or unisexual; not pentamerous throughout; departing from pentamery in the calyx and in the corolla, or in the calyx, in the corolla, and in the androecium; coloured; in panicles (corymbose); not distichous. Inflorescences lateral or on the older wood; of racemose units. Bracts absent at anthesis, or persistent beyond anthesis (small). Bracteoles present (coloured, much shorter than tube); small, not enclosing the flower buds, or relatively large and enclosing the flower buds; absent at anthesis, or persistent beyond anthesis; not valvate; free. Hypanthium present (elongate). Length of floral tube relative to total hypanthium plus calyx length, about 0.5. Calyx polysepalous; covering the rest of the flower in bud; more or less regular; 4 partite (segments petaloid, ovate); imbricate. Corolla absent. Disk absent. Androecium of fewer than ten parts; members all free of one another; members all more or less equal in length; with staminodia, or without staminodia. Fertile stamens 3–9. Anthers attached well above base of connective. Dehiscence longitudinal. Ovary stipitate; excentric with adnate stipe. Stigma not peltate (the style filiform). Ovules numerous.
Fruit, seed and seedling. Fruit a two-valved pod; becoming distinctly woody, or not becoming woody; straight, or curved; with prominent, raised veins, or without prominent raised veins; with veins other than the longitudinal ones predominating; not winged; valves twisting and enrolling during dehiscence. Seeds non-endospermic; not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons of Type 4; with a vascular system ramified throughout.
Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins mainly with abundant accompanying fibres.
Leaf lamina epidermes. Epidermal crystals present; prisms. 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; conspicuously pitted; thick. Stomata adaxially very rare. Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; conspicuously pitted in optical section; staining normally with safranin; medium-thin.
Wood anatomy. Intervascular pits very small.
Pollen ultrastructure. Tectum punctate; rugulose punctate. Length of colpi greater than one half pole to pole distance.
Cytology, geography, etc. Basic chromosome number, x = 12. 2n = 24. 8 species. Eastern Asia and Pacific. Tropical Asia. 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’.