The genera of Leguminosae-Caesalpinioideae & Swartzieae
Cymonetra Roberty, Microstegia Pierre ex Harms
Type species: G. klainei (Pierre) Vermoesen.
Habit and leaf form. Trees; unarmed.
Phyllotaxy spiral. The leaves compound; pinnate; paripinnate (but with a rachis extension). The leaflets many per leaf to few per leaf (often pellucid-punctate); opposite or sub-opposite (rarely, a few), or alternate; sessile to sub-sessile; markedly asymmetrical (the midrib more or less eccentric); with a strong, continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves; membranous. Stipels absent.
Inflorescence and floral morphology. The inflorescences axillary and terminal; branched; probably all of racemose units; panicles. The flowers distichous. Bracts absent at anthesis. Bracteoles present; small, not enclosing the flower buds; absent at anthesis; not valvate; free.
The flowers small; hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx. Hypanthium present; very short. Calyx 4; polysepalous; more or less regular; members imbricate (but subvalvate). Corolla present; regular; 5; without greatly reduced members; polypetalous. Disk absent. The androecium comprising 10 members; members all free of one another; members markedly unequal; comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary stipitate; free. Ovules few.
Fruit, seed and seedling. Fruit a two-valved pod; without markedly twisting or enrolling valves; not becoming woody. The mature valves without prominent venation. Seeds not arillate; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons not flat; 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; when seen, epithelium-lined. 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, or not seen either adaxially or abaxially; prisms. Simple unbranched hairs common, or not seen; 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; (at least some of them) thin-walled; hair feet (at least some of them) complex with vertical walls. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section, or markedly sinuous in high-focus optical section; conspicuously pitted; thin. Stomata adaxially very rare. Abaxial: Abaxial stomata predominantly paracytic. Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted in optical section; staining normally with safranin; thin.
Species number and distribution. 5 species (all formerly referred to Cynometra). Tropical Africa.
Tribe. Detarieae; Detarieae sensu stricto clade of Bruneau et al. (2008).
Miscellaneous. Illustrations: • G. kisantuense: Leonard, Fl. du Congo Belge (1952). • G. kisantuense, G. mildbraedii and G. pierreanum: Aubréville, Flore du Gabon (1968). • G. pierreanum, e.m. scanned pollen (Graham & Barker, 1981).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classification. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1993 onwards. The genera of Leguminosae-Caesalpinioideae and Swartzieae: descriptions, illustrations, identification, and information retrieval. In English and French. Version: 22nd March 2017. delta-intkey.com/caes’.