Family Theaceae
Theaceae D. DonIncluding Camelliaceae Dum., Malachodendreae (Malachodendraceae) J.G. Agardh, Ternstroemiaceae Mirb.Excluding Asteropeiaceae, Bonnetiaceae, Sladeniaceae Habit and leaf form. Trees and shrubs; non-laticiferous and without coloured juice. Plants non-succulent. Mesophytic. Leaves evergreen; alternate; spiral; leathery; petiolate; non-sheathing; not gland-dotted; without marked odour; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire, or serrate. Leaves without a persistent basal meristem. Domatia occurring in the family (Eurya); manifested as pits. Leaf anatomy. Mucilaginous epidermis present, or absent. The mesophyll with sclerencymatous idioblasts. Minor leaf veins without phloem transfer cells (4 genera). Stem anatomy. Cork cambium present; initially deep-seated, or superficial. Nodes unilacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones, or not stratified. ‘Included’ phloem absent. Xylem with tracheids, or without tracheids; with fibre tracheids, or without fibre tracheids; with vessels. Vessel end-walls horizontal to oblique; scalariform, or simple. Wood parenchyma apotracheal (usually), or apotracheal and paratracheal (in a few genera). Pith with diaphragms, or without diaphragms. Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite. Inflorescence, floral, fruit and seed morphology. Flowers usually solitary (and axillary); bi- bracteolate; medium-sized, or large; regular; cyclic, or partially acyclic. When partially acyclic, the perianth acyclic (or somewhat so). Perianth with distinct calyx and corolla, or sequentially intergrading from sepals to petals; 9–12(–50) (i.e. rarely ‘many’); (when cyclic) isomerous, or anisomerous. Calyx 5, or 7; 1 whorled; gamosepalous (usually); regular; persistent; non-accrescent; imbricate. Corolla (4–)5(–50) (rarely ‘many’); polypetalous, or gamopetalous (sometimes basally connate). Corolla lobes markedly longer than the tube. Corolla imbricate; regular. Androecium 5, or 10, or 15, or 16–100 (usually ‘many’). Androecial members branched, or unbranched; when many (i.e. usually), maturing centrifugally; free of the perianth, or adnate (to the perianth); free of one another, or coherent; when coherent 1 adelphous (the filaments united in a tube), or 5 adelphous (when bundled); 1–5 whorled. The androecial bundles at least sometimes opposite the corolla members. Androecium exclusively of fertile stamens. Stamens 5, or 10, or 15, or 16–100 (usually ‘many’); isomerous with the perianth to triplostemonous (rarely), or polystemonous (usually); alternisepalous (at least, the bundles sometimes so). Anthers dorsifixed, or basifixed; versatile, or non-versatile; dehiscing via longitudinal slits (usually), or dehiscing via short slits; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer, or initially with more than one middle layer (1 to 3). Tapetum glandular. Pollen grains aperturate; 3 aperturate; colporate (colporoidate); 2-celled. Gynoecium (2–)3–5(–10) carpelled. Carpels isomerous with the perianth, or reduced in number relative to the perianth, or increased in number relative to the perianth. The pistil (2–)3–5(–10) celled. Gynoecium syncarpous; synovarious to synstylovarious, or semicarpous (carpels united only basally in some Camellia spp.); superior (usually), or partly inferior (Visnea etc.), or inferior (Symplocarpon). Ovary (2–)3–5(–10) locular. Gynoecium stylate. Styles 2–5(–10) (as many as G); free, or partially joined. Stigmas wet type; papillate; Group III type. Placentation axile. Ovules (2–)4–50 per locule (i.e. to ‘many’); pendulous; anatropous, or campylotropous (weakly); bitegmic; tenuinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Allium-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3 (remaining uninucleate); not proliferating. Synergids pear-shaped. Hypostase present. Endosperm formation nuclear. Embryogeny solanad. Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or a berry, or a drupe. Capsules usually loculicidal (with a persistent columella). Seeds non-endospermic (usually), or endospermic (e.g. Visnea). Endosperm in Visnea oily. Seeds conspicuously hairy, or not conspicuously hairy. Cotyledons 2 (large). Embryo achlorophyllous (2/2); straight, or curved. Seedling. Germination phanerocotylar, or cryptocotylar. Physiology, biochemistry. Not cyanogenic. Alkaloids present, or absent. Iridoids not detected. Proanthocyanidins present (usually), or absent; cyanidin, or delphinidin, or cyanidin and delphinidin. Flavonols present, or absent; kaempferol and quercetin, or kaempferol, quercetin, and myricetin. Ellagic acid present (6 species, 5 genera), or absent (2 out of 4 Camellia species). Aluminium accumulation demonstrated (often), or not found. Geography, cytology. Sub-tropical and tropical. Pantropical and subtropical. X = 15, 18, 21, 25. Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Theiflorae; Theales. Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; Order Ericales. Species 500. Genera 18; Adinandra, Anneslea, Apterosperma, Archboldiodendron, Balthasaria, Camellia (including Thea), Cleyera, Eurya, Ficalhoa(?), Franklinia, Freziera, Gordonia, Pyrenaria, Schima, Stewartia, Symplocarpon, Ternstroemia (referred to Pentaphylacaceae by APG), Visnea. Economic uses, etc. Includes the commercial tea plant (Camellia sinensis), and many cultivated ornamentals. Illustrations. |
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