The

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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

''Trochetiopsis'' consists of two extant and one extinct

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 ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...

of Saint Helena (South

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

). They were formerly placed in the

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 ...

Sterculiaceae Sterculiaceae was a family of flowering plant based on the genus ''Sterculia''. Genera formerly included in Sterculiaceae are now placed in the family Malvaceae, in the subfamilies: Byttnerioideae, Dombeyoideae, Helicteroideae and Sterculioideae. A ...

, but this is included in the expanded

Malvaceae Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ...

in the APG and most subsequent systematics. There is evidence from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

pollen that the ''Trochetiopsis'' lineage has been on Saint Helena since the late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

(some 9.5 million years).

Description

The species of this genus were formerly included in the genus ''

Trochetia ''Trochetia'' is a genus of flowering plants from the family Malvaceae (formerly in the Sterculiaceae, but this family is now usually subsumed in the Malvaceae). They are endemic to the Mascarene Islands. The genus was first described by A.P. d ...

'', but were separated by Marais in 1981 on the basis of

geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, an ...

and morphological characters. Unlike in ''Trochetia'', the ''Trochetiopsis''

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 only five

stamens The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

, and the sepals generally have appressed sericeous indumentum on their interior faces (although one species, ''T. melanoxylon'', lacks this last character). The

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

of all the species is attractively coloured and is used in island inlay work.

Phylogeny

''Trochetiopsis'' is closely related to the genera '' Melhania'' and '' Paramelhania,'' with a 2021 study subsuming ''Trochetiopsis'' and ''Paramelhania'' into ''Melhania''.

Species

There are three species (two living, one extinct), and one named

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

: * ''

Trochetiopsis erythroxylon ''Trochetiopsis erythroxylon'', the Saint Helena redwood, is a species of plant, now extinct in the wild. It was formerly abundant enough in the upland parts of the island of Saint Helena for early settlers in the 17th century to use the timb ...

''. Extinct in the wild * '' Trochetiopsis ebenus''. The St Helena ebony (critically endangered in the wild). * '' Trochetiopsis melanoxylon'' - Extinct. * '' Trochetiopsis × benjaminii'' (''T. erythroxylon'' × ''T. ebenus'').

Footnotes

References

* (1981) ''Trochetiopsis'' (Sterculiaceae), a new genus from St Helena. ''Kew Bulletin'' 36(3): 645–646
HTML abstract
* (1995): ''The endemic Flora of St Helena''. Anthony Nelson Ltd, Oswestry. * (1990): The history of the endemic flora of St Helena: late Miocene ''Trochetiopsis''-like pollen from St Helena and the origin of ''Trochetiopsis''. ''New Phytologist'' 114: 159–165.

External links