Diapensiaceae is a small

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s, which includes 15

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

in 6 genera. The genera include '' Berneuxia'' Decne. (1 species), '' Diapensia'' L. (5 species), ''

Galax ''Galax'', the wandplant, wandflower, or beetleweed, is a genus in the flowering plant family Diapensiaceae, containing a single species, ''Galax urceolata'' ( syn. ''G. rotundifolia'', ''G. aphylla''). It is native to the southeastern United S ...

'' Sims (1 species), '' Pyxidanthera'' Michx. (2 species), '' Shortia'' Torr. & A.Gray (4 species), and '' Schizocodon'' Siebold & Zucc. (2 species). Members of this family have little economic importance; however, some members are cultivated by florists.

Taxonomy

Past literature classified Diapensiaceae as an old family, without defining the meaning of old. The name '' Diapensia'' was given to ''Diapensia lapponica'' by

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

. Previously, it was the Greek name of sanicle. The family, originally including only ''Diapensia lapponica'', was named by Heinrich Friedrich Link in 1829. Concerning the interrelationships in Diapensiaceae, debate still remains regarding the recognition of ''Schizocodon'' and whether it should be separate from ''Shortia''. However, recent molecular studies support the split of the two genera. Additionally, recognition of species within the genera has been debated. Within the genus ''Pyxidanthera'', two species have previously been recognized. Recent morphology and molecular work found that the two species do not differ morphologically, gene flow exists between them, and the taxa are not monophyletic. Over time, various relationships among Diapensiaceae and other angiosperm families have been proposed. Previously, it was placed within the order Rosales, as well as in the

Cornales The Cornales are an order of flowering plants, early diverging among the asterids, containing about 600 species. Plants within the Cornales usually have four-parted flowers, drupaceous fruits, and inferior to half-inferior gynoecia topped with ...

. Diapensiaceae was also placed in an order of its own in the

Cronquist system The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of Flowering Plants'' (1968; 2nd edition, 1988) ...

and by

Takhtajan Armen Leonovich Takhtajan or Takhtajian ( hy, Արմեն Լևոնի Թախտաջյան; russian: Армен Леонович Тахтаджян; surname also transliterated Takhtadjan, Takhtadzhi︠a︡n or Takhtadzhian, pronounced takh-tuh-JA ...

. Recent studies have placed Diapensiaceae as part of the

Ericales The Ericales are a large and diverse order of dicotyledons. Species in this order have considerable commercial importance including for tea, persimmon, blueberry, kiwifruit, Brazil nuts, argan, and azalea. The order includes trees, bushes, lia ...

clade, belonging to the “styracoids” (Diapensiaceae, Styracaceae, Symplocaceae). It is estimated that Diapensiaceae diverged from Sytracaceae about 93 million years ago. The family is thought to have originated in the Northern Hemisphere.

Distribution

Family Diapensiaceae members are mostly found in North America and Eastern Asia.

Characteristics

Members of Diapensiaceae are mostly herbs o
shrublets

Flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

have

radial symmetry Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, take the face of a human being which has a pla ...

, are

hypogynous In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule(s) and is located above or below or at the point of connection with the bas ...

, and have most parts arranged in whorls of 5. The ovary is made of three fused carpels. They have both ectotrophic and endotrophic mycorrhiza associations.

References

* {{Taxonbar, from=Q131417 Ericales Ericales families