''Retiniphyllum'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
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 in the
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 ...
Rubiaceae
Rubiaceae () is a family (biology), family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with Petiole ( ...
and contains 20
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), ...
.
It is the only genus in the tribe Retiniphylleae. The representatives are shrubs or small trees that grow in white sand soils in tropical South America. They are mainly distributed in the Guayana Region (
Venezuela
Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...
) but also occur in the Amazon Basin, the eastern Andes and central and eastern Brasil.
Description
The species exhibit a character that is not common in the family Rubiaceae, viz. the presence of two collateral and pendulous ovules per
locule
A locule (: locules) or loculus (; : loculi) is a small cavity or compartment within an organ or part of an organism (animal, plant, or fungus).
In angiosperms (flowering plants), the term ''locule'' usually refers to a chamber within an ovary ...
. The shrubs or trees have apical buds with abundant resin. Each flower is subtended by a bracteole and the corollas are contorted. Stamens are reflexed in anthesis and have basal and apical sterile appendages. Many species also exhibit secondary pollen presentation. The 5-locular ovary contains two ovules per locule. The drupaceous fruits contain pyrenes with one seed due to the abortion of one ovule.
Taxonomy
''Retiniphyllum'' was placed in the subfamily
Rubioideae in the earliest systems of classification due to the misinterpretation of the bi-ovulated locules.
William Jackson Hooker
Sir William Jackson Hooker (6 July 178512 August 1865) was an English botany, botanist and botanical illustrator, who became the first director of Kew Gardens, Kew when in 1841 it was recommended to be placed under state ownership as a botan ...
established the tribe Retiniphylleae in 1873 and included the genera ''Retiniphyllum'' and ''
Kutchubaea''. The classification of the group remained difficult for a long time, which resulted in the placement of the genus ''Retiniphyllum'' in different tribes and subfamilies of Rubiaceae. Molecular studies place the genus in an isolated clade of the
Ixoroideae related to
paleotropical representatives.
The monophyly of the tribe Retiniphylleae has been confirmed and the tribe is placed as a clade within the subfamily Ixoroideae.
The genera ''
Botryarrhena'' and ''
Scyphiphora'' were tentatively included in the tribe Retiniphylleae by Robbrecht (1988).
However, molecular data suggest that neither are related to ''Retiniphyllum''.
''
Botryarrhena'' is resolved within the ''
Alibertia'' group, sister to ''
Stachyarrhena'' in a clade with the genera ''
Alibertia'', ''
Borojoa'' and ''
Kutchubaea''. The monotypic genus ''
Scyphiphora'' is sister to a clade that includes the tribe
Ixoreae
''Ixora'' is a genus of flowering plants in the family Rubiaceae. It is the only genus in the tribe ''Ixoreae''. It consists of tropical evergreen trees and shrubs and holds around 544 species. Though native to the tropical and subtropical areas ...
and
Vanguerieae.
Species
* ''
Retiniphyllum cataractae''
Ducke
* ''
Retiniphyllum chloranthum''
Ducke
* ''
Retiniphyllum concolor''
(Spruce
A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...
ex Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) Müll.Arg.
* ''
Retiniphyllum discolor''
(Spruce
A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...
ex Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) Müll.Arg.
* ''
Retiniphyllum fuchsioides''
K.Krause
* ''
Retiniphyllum glabrum''
Steyerm.
* ''
Retiniphyllum guianense''
Steyerm.
* ''
Retiniphyllum kuhlmannii''
Standl.
* ''
Retiniphyllum laxiflorum''
(Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) N.E.Br.
* ''
Retiniphyllum longiflorum''
Steyerm.
* ''
Retiniphyllum maguirei''
Standl.
* ''
Retiniphyllum parvifolium''
Steyerm.
* ''
Retiniphyllum pauciflorum''
Kunth
Carl Sigismund Kunth (18 June 1788 – 22 March 1850) was a German botanist. He was also known as Karl Sigismund Kunth or anglicized as Charles Sigismund Kunth. He was one of the early systematic botanists who focused on studying the plants of th ...
ex K.Krause
* ''
Retiniphyllum pilosum''
(Spruce
A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...
ex Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) Müll.Arg.
* ''
Retiniphyllum scabrum''
Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
* ''
Retiniphyllum schomburgkii
''Retiniphyllum'' is a genus of flowering plants in the Family (biology), family Rubiaceae and contains 20 species. It is the only genus in the tribe Retiniphylleae. The representatives are shrubs or small trees that grow in white sand soils in t ...
''
(Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) Müll.Arg.
* ''
Retiniphyllum secundiflorum''
Humb.
Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 1769 – 6 May 1859) was a German polymath, geographer, naturalist, explorer, and proponent of Romantic philosophy and science. He was the younger brother of the Prussian ministe ...
& Bonpl.
* ''
Retiniphyllum speciosum''
(Spruce
A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...
ex Benth.
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...
) Müll.Arg.
* ''
Retiniphyllum tepuiense''
Steyerm.
* ''
Retiniphyllum truncatum''
Müll.Arg.
References
External links
''Retiniphyllum'' in the World Checklist of Rubiaceae
{{Taxonbar, from1=Q628706, from2=Q60212206
Rubiaceae genera
Retiniphylleae
Taxa named by Aimé Bonpland
Taxa named by Alexander von Humboldt