Buxaceae
Encyclopedia
Buxaceae are a small family
of four or five genera and about 90-120 species of flowering plant
s. They are shrub
s and small tree
s, with a cosmopolitan distribution
. A fifth genus sometimes accepted in the past (Notobuxus), has been shown by genetic studies to be included within Buxus
(Balthazar et al., 2000).
The family is recognised by most taxonomists, and is sometimes known as the box
family. However, its placement and circumscription has varied; some taxonomists treat Styloceras
in its own family Stylocerataceae, and others have included Simmondsia
(usually placed in its own family Simmondsiaceae) in Buxaceae.
The APG II system
of 2003 recognises the family, but in a new circumscription in that it includes the genus Didymeles
(two species of evergreen trees from Madagascar). However, APG II does allow the option of segregating this genus as family Didymelaceae
, as an optional segregate
. This represents a slight change from the APG system
of 1998, which firmly recognised both families as separate. In both APG and APG II the family Buxaceae is unplaced as to order and left among the basal lineages of the eudicots
. The AP website suggests instating the order Buxales
for this family and the family Didymelaceae.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of four or five genera and about 90-120 species of flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. They are shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s and small tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, with a cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
. A fifth genus sometimes accepted in the past (Notobuxus), has been shown by genetic studies to be included within Buxus
Buxus
Buxus is a genus of about 70 species in the family Buxaceae. Common names include box or boxwood ....
(Balthazar et al., 2000).
The family is recognised by most taxonomists, and is sometimes known as the box
Buxus
Buxus is a genus of about 70 species in the family Buxaceae. Common names include box or boxwood ....
family. However, its placement and circumscription has varied; some taxonomists treat Styloceras
Styloceras
Styloceras is a genus of plant in family Buxaceae. It contains the following species :* Styloceras kunthianum, Juss....
in its own family Stylocerataceae, and others have included Simmondsia
Jojoba
Jojoba, pronounced , is a shrub native to the Sonoran and Mojave deserts of Arizona, California, and Mexico. It is the sole species of the family Simmondsiaceae, placed in the order Caryophyllales. It is also known as goat nut, deer nut, pignut, wild hazel, quinine nut, coffeeberry, and gray box...
(usually placed in its own family Simmondsiaceae) in Buxaceae.
The APG II system
APG II system
The APG II system of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Group. It was a revision of the first APG system, published in 1998, and was superseded in 2009...
of 2003 recognises the family, but in a new circumscription in that it includes the genus Didymeles
Didymeles
Didymeles is a genus of flowering plants. It is variously treated in the family Buxaceae, or as the only genus of the family Didymelaceae. The genus is native to Madagascar and the Comoro Islands and consists of two species of evergreen trees:...
(two species of evergreen trees from Madagascar). However, APG II does allow the option of segregating this genus as family Didymelaceae
Didymelaceae
Didymelaceae is a family of flowering plants. The family has been recognised by a fair number of taxonomists, at least over the past few decades....
, as an optional segregate
Segregate (taxonomy)
In taxonomy, a segregate, or a segregate taxon is created when a taxon is split off, from another taxon. This other taxon will be better known, usually bigger, and will continue to exist, even after the segregate taxon has been split off...
. This represents a slight change from the APG system
APG system
The APG system of plant classification is the first, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in 1998 by the Angiosperm Phylogeny Group. It was superseded in 2003 by a revision, the APG II system, and then in 2009 by a further...
of 1998, which firmly recognised both families as separate. In both APG and APG II the family Buxaceae is unplaced as to order and left among the basal lineages of the eudicots
Eudicots
Eudicots and Eudicotyledons are botanical terms introduced by Doyle & Hotton to refer to a monophyletic group of flowering plants that had been called tricolpates or non-Magnoliid dicots by previous authors...
. The AP website suggests instating the order Buxales
Buxales
Buxales is a botanical name at the rank of order.Under the APG II system, Buxaceae is a family unplaced as to order in the eudicots. This family may optionally include the genus Didymeles, which in Cronquist system was given its own family and order, placed in subclass Hamamelidae...
for this family and the family Didymelaceae.