Theaceae

Theaceae, commonly called the tea family, consists of shrubs and trees, most of which come from China and East Asia, though some are found elsewhere. The family includes the tea plant, which is economically vital, and camellias, grown for their beauty. Depending on how the family is defined, it may contain anywhere from seven to forty genera. The family Ternstroemiaceae was once considered part of Theaceae, but the APG III system of 2009 moved it to Pentaphylacaceae.

Plants in this family have simple, glossy leaves that grow in a spiral or two-rowed pattern, with serrated edges. Most are evergreen, but *Stewartia* and *Franklinia* lose their leaves each year. The leaf teeth often have a characteristic tip that is glandular and falls off. Flowers are typically large, showy, and pink or white, often strongly scented. The calyx has five or more sepals that often remain on the fruit, and the corolla usually has five petals. These plants have many stamens—often 20 to over 100—which may be free or attached to the base of the petals. A distinctive feature is pseudopollen, produced from connective cells and marked with rib-like or circular thickenings. The ovary is often hairy and tapers into a style that may be branched or split. The carpels usually sit opposite the petals, or opposite the sepals in *Camellia*. Fruits are capsules that split open, berry-like but not splitting, or sometimes pome-like. Seeds are few, sometimes winged, sometimes covered in fleshy tissue, or bare.

Eight genera are currently accepted: *Apterosperma*, *Camellia* (which includes several former genera like *Dankia* and *Thea*), *Franklinia*, *Gordonia* (including *Laplacea*), *Polyspora*, *Pyrenaria* (including *Dubardella* and others), *Schima*, and *Stewartia* (including *Hartia*). A fossil, *Pentapetalum trifasciculandricus*, about 91 million years old, may belong to Theaceae or Pentaphylacaceae.

The family is found in Southeast Asia, Malesia, tropical South America, and the southeastern United States. Three genera—*Franklinia*, *Gordonia*, and *Stewartia*—have species native to the southeastern U.S., with *Franklinia* found only there. Under some classifications, Asian species once placed in *Gordonia* are now moved to *Polyspora*.

Chemically, Theaceae is distinctive. Single crystals of calcium oxalate sometimes occur. Ellagic acid and common polyphenols like flavonols, flavones, and proanthocyanins are widespread. Gallic acid and catechins appear only in *Camellia* section *Thea* (which includes *C. sinensis*, *C. taliensis*, and *C. irrawadiensis*). Caffeine and its precursors theobromine and theophylline are also limited to that section. In the tea bush, caffeine makes up 2.5–4% of the leaf’s dry weight; this high level of caffeine and catechins results from artificial selection by humans. Triterpenes and their saponin glycosides are found throughout the family in seeds, leaves, wood, and bark. These plants also accumulate aluminum and fluoride.

The best-known genus is *Camellia*, especially *C. sinensis*, whose leaves produce tea. In parts of Asia, other species like *C. taliensis*, *C. grandibractiata*, *C. kwangsiensis*, *C. gymnogyna*, *C. crassicolumna*, *C. tachangensis*, *C. ptilophylla*, and *C. irrawadiensis* are also used as beverages. Many species are grown as ornamentals for their flowers and foliage.