| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Siphonodontaceae Gagnep. & Tardieu

Alternatively Capusiaceae Gagnep.; ~ Celastraceae.

Habit and leaf form. Trees, or lianas. Self supporting, or climbing. Mesophytic. Leaves alternate; distichous; non-sheathing; simple. Lamina entire; pinnately veined. Leaves exstipulate.

Axial (stem, wood) anatomy. Secondary thickening developing from a conventional cambial ring, or anomalous (?).

The axial xylem with libriform fibres.

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

Inflorescence, floral, fruit and seed morphology. Flowers small; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present.

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; regular. Corolla 5; 1 whorled; polypetalous; regular.

Androecium 5. Androecial members free of the perianth (the filaments closely appressed to the disk, the anthers forming a five-rayed star at the top); free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; isomerous with the perianth; oppositisepalous; alternating with the corolla members. Anthers dehiscing via longitudinal slits. Pollen grains aperturate; 3 aperturate; porate.

Gynoecium (8–)10(–12) carpelled. Carpels increased in number relative to the perianth. The pistil (8–)10(–12) celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior to partly inferior (embedded in the hemispherical disk). Ovary (8–)10(–12) locular. Locules secondarily divided by ‘false septa’; each divided horizontally into one-ovulate locelli (each with one septum, dividing it into two superposed locelli). Gynoecium non-stylate. Stigmas represented by 5 stigmatic lines and tufts. Placentation axile. Ovules 2 per locule (one in each locellus); pendulous and ascending (the upper ascending, the lower pendulous); and their locelli superposed.

Fruit (hard-) fleshy; indehiscent; a drupe. The drupes with separable pyrenes (these bony, about 20, radiating). Seeds endospermic (the endosperm bony).

Geography, cytology. Sub-tropical to tropical. Southeast Asia, Malaysia, Northeast Australia.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Santaliflorae; Celastrales. Cronquist’s Subclass Rosidae; Celastrales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Celastrales (as a synonym of Celastraceae).

Species 5. Genera 1; only genus, Siphonodon.

General remarks. Conspicuously differing from Celastraceae sensu stricto (q.v.) in gynoecium morphology.

Illustrations. • Siphonodon celastrineus, as S. celastroides: Hutchinson. • Siphonodon celastrineus: Ding Hou, Fl. Malesiana 6 (1964). • Siphonodon celastrineus: Koorders and Valeton, Atlas der Baumgarten von Java (1913).

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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