| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Tessmannia Harms

Type species: T. africana Harms.

Habit and leaf form. Trees; unarmed.

Phyllotaxy spiral. The leaves compound; pinnate; imparipinnate, or paripinnate. The leaflets often emarginate, many per leaf; translucently punctate, without basal domatia, alternate; sessile to sub-sessile; with markedly twisted petiolules; symmetrical or nearly so; pinnately veined, with the laterals looping near the margins with a predominant ‘midrib’; without a continuous marginal nerve. Stipels absent.

Inflorescence and floral morphology. The inflorescences axillary, or terminal; unbranched, or branched; when branched, of racemose units; simple racemes, or panicles. The flowers distichous, or not distichous. Bracts small, caducous, absent at anthesis. Bracteoles present; small, not enclosing the flower buds; absent at anthesis; not valvate; free.

The flowers hermaphrodite; not pentamerous throughout; departing from pentamery in the calyx; white or green. Hypanthium absent, the androecium hypogynous. The perianth comprising distinct calyx and corolla. Calyx 4 (the sepals verrucose or warty); covering the rest of the flower in bud; polysepalous; more or less regular; members imbricate to not imbricate (subvalvate). Corolla present; slightly irregular; 5; without greatly reduced members; much exceeding the calyx, polypetalous (the petals narrowly oblanceolate-spathulate, with corrugated-plicate margins). Petals broadly clawed to sessile; imbricate; imbricate-ascending; red. Disk absent. The androecium comprising 10 members; with united members (having one member free with a glabrous filament, and nine with their filaments connate below into a thick, externally hairy sheath); members markedly unequal; comprising only fertile stamens. Fertile stamens 10 (inverted in the bud). Anthers attached well above the base of the connective; dehiscing longitudinally. Ovary hairy, stipitate; free. Stigma small, dilated (capitate on the rather long, slender, laterally inserted, glabrous, circinate style). Ovules numerous.

Fruit, seed and seedling. Fruit sometimes spiny, a two-valved pod, or indehiscent; straight; flat, sub-orbicular to obliquely oblong or obovate, becoming woody. The mature valves smooth, verrucose or setose, 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; epithelium-lined. 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 present, or not seen either adaxially or abaxially; prisms. Simple unbranched hairs common, or not seen; smooth. 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 absent. Basally bent hairs present. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; thick. Stomata adaxially very rare. Abaxial: 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. Wood not storied; with normal intercellular canals. Intervascular pits medium to large.

Pollen ultrastructure. Tectum punctate; rugulose punctate. Length of colpi greater than one half pole to pole distance.

Species number and distribution. 12 species. Tropical and Southern Africa.

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

Miscellaneous. Illustrations: • Tessmannia africana: Bot. Jahrb. 15 (1911). • T. africana and T. lescrauwaertii: Aubréville, Flore du Gabon (1968). • Tessmannia anomala: Aubréville, Flore du Gabon (1968). • Tessmannia lescrauwaertii: leaflet, abaxial epidermis (interveinal).

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: 4th August 2019. delta-intkey.com’.

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