The Actinidiaceae are a small

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s. The family has three

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

and about 360

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

and is a member of the order

Ericales The Ericales are a large and diverse order of flowering plants in the asterid group of the eudicots. Well-known and economically important members of this order include tea and ornamental camellias, persimmon, ebony, blueberry, cranberry, l ...

Distribution

They are temperate and subtropical woody

vine A vine is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas, or runners. The word ''vine'' can also refer to such stems or runners themselves, for instance, when used in wicker work.Jackson; Benjamin; Da ...

s, shrubs, and trees, native to Asia (''

Actinidia ''Actinidia'' is a genus of woody and, with a few exceptions, dioecious plants native to temperate eastern Asia, occurring throughout most of China, Taiwan, Korea, and Japan, and extending north to southern areas of Russian Far East and south ...

'' or

kiwifruit Kiwifruit (often shortened to kiwi), or Chinese gooseberry, is the edible berry (botany), berry of several species of woody vines in the genus ''Actinidia''. The most common cultivar group of kiwifruit (Actinidia chinensis var. deliciosa, ...

, ''

Clematoclethra ''Clematoclethra'' is a genus of plants in the family Actinidiaceae. It contains about 20 species and is endemic to subtropical and temperate regions of central and western China. Monophyly of the group is supported by genetic evidence and als ...

'', and '' Saurauia'') and Central America and South America ('' Saurauia'' only). ''Saurauia'', with its 300 species, is the largest genus in this family. Although now confined to Asia and tropical Central and South America, evidence indicates in the past the family had a wider distribution. The now extinct genus ''Parasaurauia'' is thought to have belonged to the Actinidiaceae and lived in North America during the early

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Characteristics

The plants are usually small trees or shrubs, or sometimes vines (''Actinidia''). The alternate, simple, spiral

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

have serrated or entire margins. They lack

stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole (botany), petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part ...

s or are minutely stipulated. They are often beset with rather flattened bristles. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s grow solitary or are aggregated in terminal

cymes In botany, an inflorescence is a group or cluster of flowers arranged on a plant's stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a main axis ( ped ...

, with free

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s and

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s. Except for members of the genus ''Clematoclethra'' which have 10 stamens, the

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s are numerous and originally attached at the back. They invert just before the flower starts expanding, so their bases become apical. The plants may be

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

, or hermaphroditic. The fruit is usually a

berry A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit although many pips or seeds may be present. Common examples of berries in the cul ...

, such as the edible kiwifruit, a cultivar from the genus ''Actinidia''.

Evidence supporting placement within the Ericales

Before genetic evidence appeared in the last 10 years, the placement of the Actinidiaceae within the Ericales was highly controversial. The

USDA The United States Department of Agriculture (USDA) is an United States federal executive departments, executive department of the Federal government of the United States, United States federal government that aims to meet the needs of commerc ...

Plants Database, a resource considered authoritative, still places the Actinidaceae within the Theales, an order which has been shown not to be

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. Placement of the Actinidiaceae within the Ericales has been strongly supported recently by genetic evidence, and contrary to previous thought, it is not a basal member of the Ericales. Multiple studies using genetic evidence now firmly place the Actinidiaceae in the Ericoid

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, a monophyletic group consisting of the

Ericaceae The Ericaceae () are a Family (biology), family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with about 4,250 known species spread acros ...

, the

Cyrillaceae The Cyrillaceae are a small family of flowering plants in the order Ericales, native to warm temperate to tropical regions of the Americas. The family comprises two genera, '' Cliftonia'' and '' Cyrilla'', each containing a single species, ''Clif ...

, the

Clethraceae The Clethraceae are a small family of flowering plants in the order Ericales, composed of two genera, '' Clethra'' and '' Purdiaea'', with approximately 75 species. They are native to warm temperate to tropical regions of Asia and the Americas, w ...

, the Sarraceniaceae, and the Roridulaceae. Further genetic evidence points to the Actinidiaceae being sister to the Roridulaceae, with the Roridulaceae and Sarraceniaceae, forming another, smaller, monophyletic group.

Evidence supporting monophyly of the Actinidiaceae

What genera were to be placed in the Actinidiaceae before recent genetic and micromorphological studies emerged was highly controversial. Before recent evidence, the genus ''Sladenia'' was often placed within the Actinidiaceae. Also, ''Saurauia'' was sometimes considered its own family. Thus, before more detailed studies started, two to four genera could be placed within the Actinidiaceae. Micromorphological characters have confirmed that ''Sladenia'' does not belong in the Actinidiaceae. Furthermore, biological characteristics of the cells, and molecular evidence have confirmed the three genera currently circumscribed in the Actinidiaceae, ''Clematoclethra'', ''Saurauia'', and ''Actinidia'', do indeed form a monophyletic group.

References

External links

Actinidiaceae
i
BoDD – Botanical Dermatology Database
{{Authority control Ericales families Taxa named by Ernest Friedrich Gilg