Gonystylaceae Van Tiegh
~ Thymelaeaceae
Habit and leaf form. Trees. Leaves alternate; leathery; petiolate; non-sheathing; gland-dotted (commonly pellucid-punctate), or not gland-dotted; simple. Lamina entire; pinnately veined (with numerous nerves). Leaves exstipulate. Lamina margins entire.
Leaf anatomy. Mucilaginous epidermis present. Stomata present; mainly confined to one surface (abaxial); cyclocytic. Hairs present; eglandular; unicellular.
Lamina dorsiventral; with secretory cavities. The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses.
Stem anatomy. Cork cambium present; initially superficial. Primary vascular tissue centrifugal. Internal phloem absent. Secondary thickening developing from a conventional cambial ring (with no intraxylary phloem, by contrast with Thymelaeaceae sensu stricto). Included phloem absent. Xylem with tracheids. Vessel end-walls simple. Vessels with vestured pits. Primary medullary rays narrow (mostly uniseriate). Wood parenchyma apotracheal to paratracheal (intermediate).
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in panicles. The terminal inflorescence unit cymose. Inflorescences terminal. Flowers regular. Free hypanthium present. Hypogynous disk absent.
Perianth with distinct calyx and corolla (unless the corolla of Hutchinson, Cronquist et al. is interpreted as an extrastaminal disk, as by Airy Shaw 1973); 1245; anisomerous. Calyx 5; 1 whorled; polysepalous, or gamosepalous (?); five blunt-lobed; regular; imbricate. Corolla 740; polypetalous (the petals 740, linear or deltoid, sometimes divided almost to the base, inserted on the hypanthium). Petals deeply bifid, or entire.
Androecium (8)30100 (usually many). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens (8)30100 (usually many); polystemonous; filantherous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits. Pollen grains aperturate; 411 aperturate (?); (oligo-) foraminate.
Gynoecium 35 carpelled. Carpels reduced in number relative to the perianth to isomerous with the perianth. The pistil 35 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 35 locular. Gynoecium stylate. Styles 1; apical; much longer than the ovary (threadlike, bent). Stigmas 1; small. Placentation apical. Ovules 1 per locule; pendulous; arillate.
Fruit non-fleshy (thick walled, becoming woody); tardily dehiscent; a capsule. Capsules loculicidal. Fruit 13 seeded. Seeds non-endospermic; large. Embryo straight.
Geography, cytology. Paleotropical. Tropical. Malaysia.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Malviflorae; Thymelaeales. Cronquists Subclass Rosidae; Myrtales. APG (1998) Eudicot; core Eudicot; Rosid; Eurosid II; Malvales (as a synonym of Thymelaeaceae). Species 30. Genera 1; (?)only genus, Gonystylus.
Economic uses, etc. Timber tree ramin.
Cite this publication as: ‘L. Watson and M. J. Dallwitz (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 14th December 2000. http://biodiversity.uno.edu/delta/’. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993, 1995, 2000), and Watson and Dallwitz (1991) should also be cited (see References).