Description from Flora of China
Kalomikta Regel; Trochostigma Siebold & Zuccarini.
Climbing shrubs, glabrous or hairy, indumentum of stellate or simple hairs; pith solid or lamellate. Branches usually with linear, lengthwise lenticels; winter buds small, enclosed in swollen base of petiole or exposed. Leaves often long petiolate; stipules minute, obsolete, or absent; leaf blade membranous, papery, or leathery, venation penniveined, veinlets reticulate, usually in cross-bars, margin serrate or dentate, rarely entire. Inflorescences cymose, axillary, often pseudo-umbellate, few- or many flowered, or flowers solitary; bracts present, minute. Flowers white, pink, red, yellow, or green, bisexual, plants polygamous or functionally dioecious. Sepals (2-)5(or 6), distinct or connate at base, imbricate, rarely valvate, persistent or not. Petals (4 or)5(or more than 5), imbricate. Stamens numerous, in functionally female flowers often with shorter filaments and smaller sterile anthers; filaments slender; anthers yellow, brown, purple, or black, versatile, attached at middle, 2-celled, dehiscing lengthwise, usually divaricate at base. Disk absent. Ovary ovoid, cylindrical, or bottle-shaped, glabrous or hairy, many loculed; ovules numerous per locule; styles as many as carpels (15-30), usually reflexed, persistent, radiating, in functionally female flower elongating after anthesis; rudimentary ovary in functionally male flower very small, with minute styles. Fruit a berry, globose, ovoid, or oblong, spotted with lenticels or not, glabrous or hairy. Seeds numerous, oblong, small, immersed in pulp; testa cartilaginous, reticulate-pitted; albumen copious and abundant; embryo comparatively large, cylindrical, straight, at center of albumen; cotyledons short.
The genus was lectotypified (Li, X. W. & J. Q. Li. 2007. Nordic J. Bot. 25: 294) after publication of the family treatment for the Flora of China.
Actinidia pentapetala R. G. Li & J. W. Li (Ann. Bot. Fenn. 43: 462. 2006) was regarded as a dubious species by X. W. Li and J. Q. Li (loc. cit.) because no fruits had been seen. The name was originally published by R. G. Li and J. W. Li (Guihaia 23: 194. 2003) but not validly so because no type was indicated (Vienna Code, Art. 37.6).
About 55 species: E and S Asia; 52 species (44 endemic) in China.