Family Kirkiaceae

Kirkiaceae (Engl.) Takht.

~ Simaroubaceae

Habit and leaf form. Trees. Leaves alternate; spiral (crowded at the branch tips); not gland-dotted; compound; (impari) pinnate; exstipulate.

Leaf anatomy. 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 (sub) centric, or isobilateral; without secretory cavities. The mesophyll without etherial oil cells; not containing mucilage cells; without sclerenchymatous idioblasts.

Stem anatomy. Secretory cavities absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Wood parenchyma paratracheal (vasicentric).

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 unit cymose. Inflorescences axillary; dichasia. Flowers 4 merous; cyclic. Floral receptacle with neither androphore nor gynophore. 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 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order unassigned to Order (but presumably Sapindales).

Species 8. Genera 1; only genus, Kirkia.

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.