The Genera of Leguminosae-Caesalpinioideae and Swartzieae
The Genera of Leguminosae-Caesalpinioideae and Swartzieae | |
Habit and leaf form. Trees (with young leaves often brightly coloured); without tendrils; unarmed. Phyllotaxy distichous, or spiral. Leaves compound; pinnate; paripinnate. Venation neither palmate nor parallel nor fan-like (but tending to be palmate in the base of the lower half of the asymmetric leaflet. cf Monopetalanthus and Aphanocalyx, where upper half of leaflet is more reduced). Leaflets many per leaf, or few per leaf; markedly asymmetrical at the base; opposite or sub-opposite; without a continuous marginal nerve; sessile to sub-sessile; with markedly twisted petiolules, or with petiolules not noticeably twisted (rare). Stipules absent or early caducous or very inconspicuous, or present, persistent and conspicuous; leafy, or neither leafy nor spinescent; connate, or not connate. Stipels present, or absent.
Inflorescence and floral morphology. Flowers hermaphrodite; not pentamerous throughout (calyx and corolla together 1–11, often rudmentary or absent); departing from pentamery in the calyx and in the corolla; in simple racemes, or in panicles; distichous (rare), or not distichous. Inflorescences terminal (usually; rarely lateral on older branchlets). Bracts absent at anthesis. Bracteoles present; relatively large and enclosing the flower buds; persistent beyond anthesis; valvate. Hypanthium present. Length of floral tube relative to total hypanthium plus calyx length, about 0.5. Calyx polysepalous. Corolla present; very zygomorphic; polypetalous; including greatly reduced petals. Clawed petals absent. Disk present and conspicuous, or absent. Androecium of ten parts, or of more than ten parts (rare); with united members, or members all free of one another (often obscurely diadelphous); members all more or less equal in length, or members markedly unequal; with staminodia, or without staminodia. Fertile stamens 10, or 10–18 (rare). Anthers attached well above base of connective. Dehiscence longitudinal. Ovary stipitate; free. Ovules numerous.
Fruit, seed and seedling. Fruit a two-valved pod; becoming distinctly woody; with veins other than the longitudinal ones predominating; conspicuously winged; valves twisting and enrolling during dehiscence. Seeds non-endospermic; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons of Type 4; with a vascular system in one plane; epigeal.
Transverse section of lamina. Leaves with conspicuous phloem transfer cells in the minor veins. Druses absent from the mesophyll. Mesophyll secretory cavities (gland-dots) common, or absent. Adaxial hypodermis absent. Leaf girders common (the veins transcurrent), or absent. Laminae dorsiventral. 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 common; scabrid. No compound or branched eglandular hairs seen. Capitate glands not seen. Hooked hairs not seen. Cassieae-type leaf pseudo-glands not seen. Expanded and embedded hair-feet present, or absent; all medium to thick-walled, or (at least some of them) thin-walled; hair feet (at least some of them) complex with vertical walls, or all simple, without vertical walls. Basally bent hairs absent. Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted, or not conspicuously pitted; medium-thin. Stomata adaxially common and widespread, or adaxially very rare. Abaxial stomata predominantly paracytic. Abaxial epidermis papillate interveinally, or not papillate; with the papillae not over-arching the stomata. Abaxial interveinal epidermal cell walls straight, or gently undulating, or markedly sinuous in high-focus optical section; conspicuously pitted in optical section, or not conspicuously pitted in optical section; staining normally with safranin; of medium thickness to medium-thin.
Wood anatomy. Wood without septate fibres; storied; without normal intercellular canals; without traumatic canals. Intervascular pits medium to large.
Pollen ultrastructure. Tectum reticulate; strongly irregularly coarse-reticulate. Length of colpi greater than one half pole to pole distance. Foot layer of pollen wall smooth.
Cytology, geography, etc. Basic chromosome number, x = 12. 2n = 24. 30 species. Africa. Tropical and southern Africa. Not widely cultivated.
Tribe. Detarieae (Amherstieae of Cowan and Polhill 1981).
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’.