Aceraceae were recognized as a family of

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 also called the maple family. They contain two to four genera, depending upon the circumscription, of some 120

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), ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s and

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s. A common characteristic is that the leaves are

opposite In lexical semantics, opposites are words lying in an inherently incompatible binary relationship. For example, something that is ''even'' entails that it is not ''odd''. It is referred to as a 'binary' relationship because there are two members i ...

, and the fruit a

schizocarp A schizocarp is a dry fruit that, when mature, splits up into mericarps. There are different definitions: * Any Dry fruits, dry fruit composed of multiple carpels that separate. : Under this definition the mericarps can contain one or more ...

. The maples have long been known to be closely related to the family

Sapindaceae The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Examples include Aesculus, horse chestnut, maples, ackee and lychee. The ...

. Several

taxonomists In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon), and these groups are given ...

(including the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

) now include both the Aceraceae and the

Hippocastanaceae Hippocastanoideae is a Family (biology), subfamily of flowering plants in the Sapindus, soapberry family Sapindaceae. The group was formerly treated as the separate families Aceraceae and Hippocastanaceae. molecular phylogeny, Molecular phylogene ...

in the Sapindaceae. Recent research (Harrington et al. 2005Harrington, M. G., Edwards, K. J., Johnson, S. A., Chase, M. W., & Gadek, P. A. (2005). Phylogenetic inference in Sapindaceae sensu lato using plastid matK and rbcL DNA sequences. ''Systematic Botany'' 30: 366-382
Abstract
) has shown that while both Aceraceae and Hippocastanaceae are monophyletic in themselves, their removal from

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'' would leave Sapindaceae ''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

'' as a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

group, particularly with reference to the genus '' Xanthoceras''.

Gallery

Acer rubrumAH.jpg, ''

Acer saccharinum ''Acer saccharinum'', commonly known as silver maple, creek maple, silverleaf maple, soft maple, large maple, water maple, swamp maple, or white maple, is a species of maple native to the eastern and central United States and southeastern Canad ...

'' AcerPalmatum.jpg, ''

Acer palmatum ''Acer palmatum'', commonly known as Japanese maple, palmate maple, or smooth Japanese maple (Korean: ''danpungnamu'' []; Japanese: ''irohamomiji'' [] or ''momiji'' []), is a species of woody plant native to Korea, Japan, China, eastern Mongol ...

References

Sapindaceae Historically recognized angiosperm families {{sapindales-stub