Buxales

▪ plant order

 the boxwood order of dicotyledonous flowering plants, comprising Buxaceae (90–120 species in 4–5 genera) and the small family Didymelaceae (Didymelales) (2 species in 1 genus). These families are closely related and are sometimes merged into a single family, Buxaceae. Buxales belongs to a group of plants known as the basal eudicots, together with Gunnerales, Proteales, Ranunculales, Sabiales, and Trochodendrales, in the Angiosperm Phylogeny Group II (APG II) botanical classification system (see angiosperm).

      The largest genus in Buxaceae is the widely cultivated Buxus (boxwood), with about 70 species. These are generally woody plants with small, separate male and female flowers (usually monoecious, or on the same plant). The leaves lack stipules, and the flowers have a rather inconspicuous perianth. The styles of the female flowers are unusual in being receptive (stigmatic) for their entire length, sometimes even extending down onto the ovary itself. The male flowers have the anthers opposite the perianth lobes. Sarcococca (sweet box) is the next largest genus in Buxaceae, with about 20 species native to Asia. Pachysandra has four species, three native to East Asia and one to eastern North America. The most widely cultivated species is Pachysandra terminalis, which is native to Japan and is widely cultivated as an herbaceous ground cover in most temperate regions.

      Didymelaceae, with one genus (Didymeles) and two species (D. integrifolia and D. perrieri) endemic to Madagascar, are trees with spiral, entire, greenish-drying leaves that are covered by a layer of small scales. The small unisexual flowers lack sepals or petals and occur on separate trees; the male trees have staminate flowers with just two anthers, and the female have pistillate flowers with a long, oblique stigma, a single carpel, and one ovule.

Paul E. Berry

 

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