The families of flowering plants

L. Watson and M.J. Dallwitz

Actinidiaceae Van Tiegh.

Including Sauraujeae (Sauraujaceae) J.G. Agardh, Saurauiaceae J.G. Agardh corr. Hutch.

Habit and leaf form. Trees, or shrubs, or lianas. Self supporting, or climbing. Mesophytic. Leaves alternate; spiral; non-sheathing; not gland-dotted; simple. Lamina entire; pinnately veined; cross-venulate. Leaves minutely stipulate. Stipules caducous. Lamina margins entire, or serrate.

General anatomy. Plants with ‘crystal sand’ (dubiously, in the phloem), or without ‘crystal sand’.

Leaf anatomy. The leaf lamina dorsiventral. Stomata present; mainly confined to one surface (abaxial); anomocytic. Hairs present (including simple, unicellular, multicellular, uniseriate, branched and unbranched, clustered, shaggy, eglandular and glandular forms); eglandular, or glandular; unicellular, or multicellular. Lamina without secretory cavities. The mesophyll without sclerenchymatous idioblasts; containing crystals. The crystals raphides (in elongate sacs or tubes). Minor leaf veins without phloem transfer cells (Actinidia).

Axial (stem, wood) anatomy. Young stems with solid internodes, or with spongy internodes, or with hollow internodes. Pith with diaphragms, or without diaphragms. Secretory cavities absent. Cork cambium present; initially deep-seated, or initially superficial. Nodes unilacunar (usually), or tri-lacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The wood diffuse porous. The vessels small, or small and medium (then “locally zonate””); mostly solitary. The vessel end-walls oblique; simple, or scalariform and simple. The vessels without vestured pits; commonly with spiral thickening. The axial xylem with tracheids; without vasicentric tracheids; with fibre tracheids; without septate fibres. The fibres without spiral thickening. The parenchyma apotracheal; wood not storied.

Reproductive type, pollination. Plants hermaphrodite, or monoecious, or dioecious.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when aggregagated, in cymes. The ultimate inflorescence units cymose. Inflorescences axillary (sometimes on old wood); usually small cymose clusters. Flowers often bracteolate (with small bracteoles); regular; (4–)5(–7) merous. Free hypanthium absent.

Perianth with distinct calyx and corolla; (8–)10(–14); 2 whorled; isomerous. Calyx (4–)5(–7); 1 whorled; polysepalous; regular; persistent; accrescent (often), or non-accrescent; imbricate. Corolla (4–)5(–7); 1 whorled; polypetalous; imbricate; regular; deciduous.

Androecium (10–)18–100 (usually numerous). Androecial members branched, or unbranched; maturing centrifugally; free of the perianth; all equal; free of one another, or coherent (then variously united at the base, often in five clusters opposite the petals). Androecium exclusively of fertile stamens. Stamens (10–)18–100 (usually many); diplostemonous to polystemonous; erect in bud, or inflexed in bud. Anthers dorsifixed; becoming inverted during development, their morphological bases ostensibly apical in the mature stamens; versatile; dehiscing via pores to dehiscing via short slits (these ostensibly apical), or dehiscing via longitudinal slits. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with more than one middle layer (2 or 3). Tapetum glandular. Pollen shed in aggregates, or shed as single grains; when aggregated, in tetrads. Pollen grains aperturate; 3 aperturate; colporate; 2-celled.

Gynoecium 5–20 carpelled (or more?). Carpels increased in number relative to the perianth. The pistil (4–)5–30 celled (or more). Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary (4–)5–30 locular (or more — equalling the capels). Gynoecium stylate. Styles free to partially joined; often from a depression at the top of the ovary; apical. Stigmas (4–)5–30 (or more); dry type; papillate; Group II type. Placentation axile. Ovules 15–50 per locule (or more - ‘many’); non-arillate; anatropous; unitegmic; tenuinucellate. Endothelium feebly differentiated. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids elongated. Hypostase present. Endosperm formation cellular. Embryogeny solanad.

Fruit fleshy, or non-fleshy; dehiscent (when capsular), or indehiscent; a berry, or a capsule (less commonly). Capsules more or less loculicidal. Seeds endospermic. Endosperm oily (or proteinaceous). Seeds small. Cotyledons 2. Embryo achlorophyllous (1/2); straight, or curved. Polyembryony recorded (common).

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Actinidia, Saurauia. Not cyanogenic. Alkaloids present (rarely), or absent. Anthraquinones detected (Actinidia); polyacetate derived. Verbascosides not detected. Arbutin absent. Iridoids detected; ‘Route I’ type (normal). Saponins/sapogenins absent. Proanthocyanidins present; cyanidin, or cyanidin and delphinidin. Flavonols present; quercetin, or kaempferol and quercetin. Ellagic acid absent (Actinidia).

Geography, cytology. Tropical and Eastern Asia to northern Australia.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Ericales. Cronquist’s Subclass Dilleniidae; Theales. APG III core angiosperms; core eudicot; Superorder Asteranae. APG IV Order Ericales.

Species 350. Genera 3; Actinidia, Clematoclethra, Saurauia.

Economic uses, etc. Some edible fruits, including A. chinensis (‘Kiwi fruit’, ‘Chinese gooseberry’), some ornamentals.

Illustrations. • Actinidia chinensis: Bot. Mag. 140 (1914). • Actinidia chinensis: Hook. Ic. Pl. 16 (1887). • Actinidia, Clematoclethra (Chittenden). • Clematoclethra scandens ssp. hemsleyi, as C. hemsleyi: Hook. Ic. Pl. 29 (1906). • Saurauia leucocarpa, as S. barbigera: Hook. Ic. Pl. 4 (1841). • Saurauia pedunculata: Hook. Ic. Pl. 4 (1841). • Leaf hairs of Saurauia napaulensis and S. spadicea: Solereder, 1908. • leaf anatomical details of Saurauia napaulensis, with Guttiferae (Caraipa) and Theaceae (Cleyera, Freziera): Solereder, 1908.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or 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 or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 15th April 2018.’.