| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Kirkiaceae (Engl.) Takht.

~ Simaroubaceae.

Habit and leaf form. Trees. Leaves alternate; spiral (crowded at the branch tips); without marked odour; compound; epulvinate; pinnate; imparipinnate; exstipulate.

Leaf anatomy. The leaf lamina (sub) centric, or bifacial. Extra-floral nectaries absent. Abaxial epidermis not papillose. Mucilaginous epidermis present (in at least some species). Stomata present; mainly confined to one surface (abaxial); anomocytic. Adaxial hypodermis absent. Lamina without secretory cavities. The mesophyll without etherial oil cells; not containing mucilage cells; without sclerenchymatous idioblasts.

Axial (stem, wood) anatomy. Secretory cavities absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring.

The parenchyma paratracheal (vasicentric). ‘Included’ phloem absent.

Reproductive type, pollination. Unisexual flowers present. Plants monoecious, or polygamomonoecious.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence units cymose. Inflorescences axillary; dichasia. Flowers 4 merous; cyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; quadrangular, fleshy.

Perianth with distinct calyx and corolla; 8; 2 whorled; isomerous. Calyx 4; 1 whorled; gamosepalous (small); regular. Corolla 4; 1 whorled; polypetalous (much exceeding the calyx); induplicate imbricate; regular.

Androecium 4. Androecial members free of the perianth; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 4; isomerous with the perianth; oppositisepalous; filantherous (the filaments slender). Anthers dehiscing via longitudinal slits; introrse. Pollen grains aperturate; 3 aperturate; (syn-) colporate.

Gynoecium 4 carpelled. Carpels isomerous with the perianth. The pistil 4 celled. Gynoecium syncarpous; synovarious; superior (partly immersed in the disk). Ovary 4 locular. Gynoecium stylate. Styles 4 (each carpel with a short, erect style with a punctiform stigma); free; apical. Stigmas 4. Placentation axile to apical. Ovules 1 per locule; pendulous.

Fruit non-fleshy (dry); a schizocarp. Mericarps 4; comprising achenes, or comprising nutlets (the fruit splitting longitudinally into four linear-oblong, dorsally compressed, indehiscent, one-seeded carpels with a leathery endocarp, attached above to a central carpophore). Seeds non-endospermic.

Geography, cytology. Paleotropical and Cape. Sub-tropical to tropical. Tropical and South Africa.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Rutales (?). Cronquist’s Subclass Rosidae; Sapindales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order unassigned (but presumably Sapindales).

Species 8. Genera 1; only genus, Kirkia.

General remarks. Note that satisfactory representation of recent notions on the proper dispositions of several genera previously referred to Simaroubaceae will necessitate thorough overhaul of the descriptions presented in this package (cf. Ixonanthaceae, Irvingiaceae, Picramniaceae, Simaroubaceae, Surianaceae, Stylobasiaceae).

Illustrations. • Kirkia acuminata: Hook. Ic. Pl. 40 (1867). • Kirkia.

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, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 8th June 2026. delta-intkey.com’.

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