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The genera of Leguminosae-Caesalpinioideae & Swartzieae

L. Watson and M.J. Dallwitz

Cynometra L.

Cynomora Hedw., Iripa Adans., Metrocynia Thou.; Including Micklethwaitia (C. carvalhoi) and Normandiodendron (C. bequaertii and C. romii)

Type species: C. cauliflora L.

Habit and leaf form. Trees, or shrubs; unarmed.

Phyllotaxy distichous, or spiral. The leaves compound, or ostensibly simple (rarely unifoliolate, e.g. C. leptoclada); when unifoliolate, pinnately veined with a predominant midrib; pinnate, or bifoliolate; imparipinnate (rarely?), or paripinnate. The leaflets few per leaf (usually 1–4(-6) pairs); opposite or sub-opposite; petiolulate, or sessile to sub-sessile; with markedly twisted petiolules, or without noticeably twisted petiolules; markedly asymmetrical to symmetrical or nearly so; of pinnate leaves, with a predominant ‘midrib’; without a continuous marginal nerve. Stipules absent or early caducous or very inconspicuous in mature leaves; intrapetiolar, not connate (but joined at base). Stipels absent.

Inflorescence and floral morphology. The inflorescences variously disposed, sometimes on trunk or branches; unbranched, or branched; when branched, of racemose units; often short and dense, simple racemes, or fascicles, or panicles. The flowers not distichous. Bracts absent at anthesis. Bracteoles present, or absent; when present, small, not enclosing the flower buds; usually absent at anthesis; not valvate; free.

The flowers small; hermaphrodite; pentamerous, or not pentamerous throughout (rarely); departing from pentamery (when this occurs, i.e. rarely) in the calyx and in the corolla, or in the calyx, in the corolla, and in the androecium; white or green, or coloured. Floral tube length relative to total hypanthium + calyx length about 0.25. Hypanthium present; saucer-shaped to cupular (or funnel-shaped). The perianth comprising distinct calyx and corolla. Calyx (4–)5; covering the rest of the flower in bud; Swartzieae type (closed before flowering, splitting more or less irregularly into valvate lobes or teeth); very shortly gamosepalous, or polysepalous; more or less regular; members very imbricate. Corolla present; regular to slightly irregular; (4–)5; without greatly reduced members (the petals equal or nearly so); polypetalous. Petals sessile; imbricate; imbricate-ascending; white. Disk absent. The androecium comprising (8–)10(–12) members; with united members (rarely), or members all free of one another; members all more or less equal in length; comprising only fertile stamens. Fertile stamens (8–)10(–12). Anthers attached well above the base of the connective (but sagittate below); dehiscing longitudinally. Ovary stipitate; free, or eccentric, with the stipe adnate (then only slightly so). Stigma somewhat dilated, or not dilated. Ovules few (usually), or solitary ((1-)2(-4)).

Fruit, seed and seedling. Fruit a two-valved pod, or indehiscent; straight (rarely), or curved; valves twisting and enrolling during dehiscence, or without markedly twisting or enrolling valves; becoming woody, or not becoming woody. The mature valves with conspicuous, prominent, raised venation, or without prominent venation; conspicuous venation if present, not predominantly longitudinal. Seeds non-endospermic; with a straight or slightly oblique radicle; amyloid-positive. Cotyledons not flat; of Type 4; with a vascular system ramified throughout; 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; epithelium-lined. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll exhibiting fibres or sclereids which are unaligned with the vascular bundles. 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: Adaxial interveinal epidermal cell walls markedly sinuous in high-focus optical section; conspicuously pitted, or not conspicuously pitted; of medium thickness. Stomata adaxially very rare. Abaxial: 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; of medium thickness.

Wood anatomy. Wood with septate fibres, or without septate fibres; storied, or not storied; without normal intercellular canals; without traumatic canals. Intervascular pits very small.

Pollen ultrastructure. Tectum reticulate, or striate; rugulose reticulate; interwoven striate. Length of colpi greater than one half pole to pole distance.

Species number and distribution. About 80 species (excluding Zenkerella). Tropics.

Tribe. Detarieae; Amherstieae clade of Bruneau et al. (2008).

Miscellaneous. Illustrations: • C. spruceana: Fl. Brasiliensis 15 (1870). • C. cauliflora: Fl. Males. 12 (1996). • C. engleri: Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • C. suaheliensis (as Schotia)): Engler & Drude, Pflanzenwelt Afrikas 9 (1915). • C. alexandri, 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.’.