The Families of Flowering Plants
The Families of Flowering Plants | |
~ Theaceae
Habit and leaf form. Trees. Leaves alternate; non-sheathing; simple. Lamina entire; pinnately veined. Leaves exstipulate. Lamina margins serrate, or dentate.
Leaf anatomy. Stomata present; mainly confined to one surface (the lower); anomocytic.
The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses (no raphides).
Stem anatomy. Cork cambium present; initially superficial. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Vessel end-walls oblique; scalariform.
Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present. Nectar secretion from the gynoecium (from the lower, glandular ribs).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The terminal inflorescence unit cymose. Inflorescences axillary; short dichasial cymes. Flowers regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk absent.
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; persistent; much imbricate. Corolla 5; 1 whorled; polypetalous (the petals as long as the sepals); imbricate; regular. Petals entire.
Androecium 10(–13). Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 10(–13); isomerous with the perianth to diplostemonous; filantherous (the filaments broad, more or less ovate, thick, abruptly attenuate above). Anthers basifixed (sagittate); dehiscing via pores (‘poriform slits’); introrse. Pollen grains aperturate; 3 aperturate; colporate (colporoidate).
Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth. The pistil 3 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior (ovary with 10 thickened and glandular ribs below, simulating a disk, and 20-ribbed above). Ovary 3 locular. Gynoecium stylate. Styles 1, or 3 (‘the ovary narrowed into a thick, shortly trifid style’); attenuate from the ovary; apical. Stigmas 3. Placentation axile, or apical. Ovules 2 per locule; pendulous; collateral; with a long, beaked appendage near the funicle.
Fruit non-fleshy; dehiscent, or a schizocarp (not known in the mature state — with crustaceous endocarp and papery exocarp, possibly splitting septicidally into three cocci). Mericarps if schizocarpic, 3. Seeds winged.
Geography, cytology. Paleotropical. Sub-tropical to tropical. Burma, Yunnan, Siam.
Taxonomy. Subclass Dicotyledonae; Tenuinucelli (?). Dahlgren’s Superorder Theiflorae (?); Theales (? - cf. Theaceae). Cronquist’s Subclass Dilleniidae; Theales. APG (1998) family of uncertain position at the highest group level. Species 1. Genera 1; only genus, Sladenia.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, genera included in each family, classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG), and notes on the APG classification.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 10th April 2008. http://delta-intkey.com’.