''Stylidium'' subg. ''Centridium'' is a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

of ''

Stylidium ''Stylidium'' (also known as triggerplants or trigger plants) is a genus of dicotyledonous plants that belong to the family Stylidiaceae. The genus name ''Stylidium'' is derived from the Greek ''στύλος'' or ''stylos'' (column or pillar), w ...

'' that is characterized by a globose hypanthium, a stipitate brush-like stigma, and gynostemium mobility not produced by a sensitive hinged torosus but by the movement of a cunabulum. All species with the possible and doubtful exception of ''S. weeliwolli'' are annuals.Lowrie, A. and Kenneally, K.F. (1998). Three new triggerplant species in ''Stylidium'' subgenus ''Centridium'' (Stylidiaceae) from Western Australia. ''Nuytsia'', 12(2): 197-206. This subgenus appears to be most closely related to the genus ''

Levenhookia ''Levenhookia'', also known as the styleworts, is a genus of ten recognized species in the family Stylidiaceae and is endemic to Australia. The genus is restricted to Western Australia almost exclusively with a few exceptions: '' L. pusilla ...

'', which suggests an ancestral relationship.Carlquist, S. (1969). Studies in Stylidiaceae: New taxa, field observations, evolutionary tendencies. ''Aliso'', 7(1): 13-64. ''Centridium'' was first published by

John Lindley John Lindley FRS (5 February 1799 – 1 November 1865) was an English botanist, gardener and orchidologist. Early years Born in Catton, near Norwich, England, John Lindley was one of four children of George and Mary Lindley. George Lindley ...

in the 1839 publication, ''

A Sketch of the Vegetation of the Swan River Colony "A Sketch of the Vegetation of the Swan River Colony", also known by its standard botanical abbreviation ''Sketch Veg. Swan R.'', is an 1839 article by John Lindley on the flora of the Swan River Colony. Nearly 300 new species were published in it, ...

''. Lindley created this subgenus to distinguish species which did not fit into either of the two other subgenera that had existed at the time. He initially placed ''

Stylidium calcaratum ''Stylidium'' (also known as triggerplants or trigger plants) is a genus of dicotyledonous plants that belong to the family Stylidiaceae. The genus name ''Stylidium'' is derived from the Greek ''στύλος'' or ''stylos'' (column or pillar), w ...

'', the newly described '' Stylidium androsaceum'', and ''

Stylidium stipitatum ''Levenhookia stipitata'', the common stylewort, is a dicotyledonous plant that belongs to the genus ''Levenhookia'' (family Stylidiaceae). It is an ephemeral annual that grows about tall with oblanceolate to linear leaves. Flowers are pink an ...

'' into subgenus ''Centridium''. His description of ''S. androsaceum'' turned out to be synonymous with ''S. calcaratum'' and ''S. stipitatum'' is a synonym of ''

Levenhookia stipitata ''Levenhookia stipitata'', the common stylewort, is a dicotyledonous plant that belongs to the genus ''Levenhookia'' (family Stylidiaceae). It is an ephemeral annual that grows about tall with oblanceolate to linear leaves. Flowers are pink an ...

''.

References

Stylidium Plant subgenera {{Stylidiaceae-stub

See also

References