| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Heteropyxidaceae Engler & Gilg

~ Myrtaceae-Psiloxyloideae p.p.

Habit and leaf form. Small trees. Leaves alternate; spiral; petiolate; non-sheathing; gland-dotted (pellucid punctate); simple. Lamina entire; pinnately veined (without an intramarginal vein); cross-venulate. Leaves stipulate. Lamina margins entire. Domatia occurring in the family; manifested as pockets.

Leaf anatomy. Lamina with secretory cavities.

Axial (stem, wood) anatomy. Internal phloem present (?). Secondary thickening developing from a conventional cambial ring.

The axial xylem with fibre tracheids; without libriform fibres.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles. Inflorescences terminal; terminal thyrses. Flowers small; regular; 5 merous; cyclic; tetracyclic. Free hypanthium present (the corolla ‘inserted on the calyx tube’).

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous, or gamosepalous; five blunt-lobed; regular; persistent; scarcely imbricate, or open in bud. Corolla 5; 1 whorled; polypetalous (the small petals inserted on the hypanthium/calyx tube). Petals shortly clawed (and gland dotted).

Androecium 5. Androecial members free of the perianth (inserted on the tube); all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; alternisepalous; opposite the corolla members; inflexed in bud. Anthers dorsifixed; dehiscing via longitudinal slits; introrse; appendaged (with a well developed connective gland). The anther appendages apical. Pollen grains aperturate; 3 aperturate; (parasyn-) colporate.

Gynoecium 2–3 carpelled. Carpels reduced in number relative to the perianth. The pistil 2–3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 2–3 locular; sessile. Gynoecium stylate. Styles 1; from a depression at the top of the ovary; apical; short, persistent. Stigmas 1; capitate. Placentation axile (the ovules over most of the peltate placenta). Ovules 30–50 per locule (‘many’, no ovulodes); hemianatropous, or campylotropous (?).

Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal (small, 2–3 locular). Seeds non-endospermic. Cotyledons 2; flat. Embryo straight.

Geography, cytology. Paleotropical. Tropical. South Africa.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Myrtiflorae; Myrtales. Cronquist’s Subclass Rosidae; Myrtales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Myrtales (as a synonym of Myrtaceae).

Species 3. Genera 1; only genus, Heteropyxis.

General remarks. Seemingly differing from Myrtaceae in inflorescence, androecium and gynoecium characters; but as is often the case in such situations, the extent of intra-taxon variation within the large family may have been under-estimated.

Illustrations. • Heteropyxis canescens (Hutchinson). • Heteropyxis canescens: Hook. Ic. Pl. 25 (1895).

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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