| # The genera of Leguminosae-Caesalpinioideae and Swartzieae |

L. Watson and M.J. Dallwitz

### Colvillea Boj. ex Hook.

Type species: C. racemosa Boj.

Habit and leaf form. Deciduous trees; unarmed.

Phyllotaxy spiral. The leaves compound; bipinnate; with opposite or sub-opposite pinnae (6–16 pairs); with opposite or sub-opposite leaflets; with adaxially grooved rachides. The leaflets small, entire, many per leaf; shortly petiolulate; without noticeably twisted petiolules; symmetrical or nearly so; with a predominant ‘midrib’. Stipules absent or early caducous or very inconspicuous in mature leaves (small, caducous); membranous. Stipels present (according to Du Poy & Moat), or absent (judging from illustrations, including theirs).

Inflorescence and floral morphology. The inflorescences large, robust, many-flowered terminal; branched; panicles (these dense, sub-erect, with pendulous secondary axes). The flowers not distichous. Bracts coloured, absent at anthesis (caducous). Bracteoles absent; absent at anthesis.

The flowers apparently strongly adapted for bird pollination, showy (about 5 cm long); hermaphrodite; very irregular (resupinate); pentamerous; coloured (the sepals orange, the petals bright red). Hypanthium present; very short; saucer-shaped. The perianth comprising distinct calyx and corolla. Calyx present; 5; covering the rest of the flower in bud; tangerine-orange, gamosepalous (the 4 upper sepals connate into a 4-toothed spathe which is held adaxially in the resupinate flower, the other member free); markedly irregular (2-lipped); members induplicate, not imbricate. Corolla present; very irregular (with the morphologically adaxial three held uppermost in the resupinate flower being largely enclosed by the spathe of the calyx, the vexillum broader with inrolled margins constituting a nectariferous cone, and with the two abaxial members held adaxially and exserted on either side of the free sepal and the stamen cluster); 5; without greatly reduced members. Well developed petals 5. Corolla polypetalous. Petals clawed; imbricate; according to Hutchinson, imbricate-ascending (?); red. Disk absent. The androecium comprising 10 members; declinate; members all free of one another; members declinate; comprising only fertile stamens. Fertile stamens 10. Anthers attached well above the base of the connective; dehiscing introrsely; dehiscing longitudinally. Ovary sessile or subsessile; free. Stigma not dilated (minute on the slender style, which is exserted beyond the stamens). Ovules numerous.

Fruit, seed and seedling. Fruit a follicle (i.e., dehiscing along one side only); large, flat, narrowly oblong, pendulous, straight; not internally septate; without markedly twisting or enrolling valves; leathery, not becoming woody. The mature valves without prominent venation. Seeds with a straight or slightly oblique radicle; amyloid-negative; with galactomannan. Cotyledons of Type 2; epigeal.

Transverse section of lamina. Leaves without conspicuous phloem transfer cells in the minor veins. Druses common in the mesophyll. Mesophyll secretory cavities absent. Adaxial hypodermis absent. Leaf girders absent. Laminae dorsiventral. Mesophyll without unaligned fibres or sclereids. Minor veins lacking accompanying fibrous tissue.

Leaf lamina epidermes. Epidermal crystals not seen either adaxially or abaxially. Simple unbranched hairs common; 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 absent. Adaxial: Adaxial interveinal epidermal cell walls straight in optical section; conspicuously pitted; thin. Stomata adaxially very rare. Abaxial: Abaxial stomata not predominantly paracytic (anomcytic, actinocytic and cyclocytic). Abaxial epidermis not papillate. Abaxial interveinal epidermal cell walls straight, or gently undulating; conspicuously pitted in optical section; scarcely staining with safranin; thin.

Pollen ultrastructure. Tectum reticulate; finely to moderately regularly reticulate. Length of colpi greater than one half pole to pole distance (without a margocolpus). Foot layer of pollen wall with obvious projections.

Cytology. Basic chromosome number, x = 14. 2n = 28.

Species number and distribution. 1 species (C. racemosa). Madagascar.

Tribe. Caesalpinieae.

Comments. Widely cultivated.

Miscellaneous. Illustrations: • Colvillesa racemosa: Bot. Mag. 61 (1834).

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’.

Contents