''Richea sprengelioides'' is a

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 ...

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 ...

in the family

Ericaceae The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...

. It is one of the 11 species within the genus ''

Richea ''Richea'' is a genus of 11 species of flowering plants in the family Ericaceae. Nine of the species are endemic to Tasmania and the other two are endemic to the south-east of the Australian mainland. Species include: *'' Richea acerosa'' (Lin ...

'' that are

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 elsew ...

to Australia, of which 9 are found only in

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. The species was first formally described by botanist Robert Brown in 1810 in ''

Prodromus Florae Novae Hollandiae ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Novae ...

''. He gave it the name ''Cystanthe sprengelioides''. /sup> In 1867 Victorian Government Botanist

Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...

transferred the species to the genus ''

''. It is found throughout the mountainous regions of Tasmania.

Description

Richea sprengelioides individual from Mt Wellington

''Richea sprengelioides'' can grow as an erect shrub up to 1.2m in height. Older stems are devoid of leaves but bear numerous angular scars. Its leaves follow the distinctive habit of its genus, sheathing the stem before curling away and tapering to a point. Its inflorescence is roughly 2 centimeters wide and tall, with some 20 flowers clustered together at the end of the stems. ''Richea sprengelioides'' in general is easily identified though it may be confused with a couple of other species found in Tasmania. One of the main features that distinguish ''R. sprengelioides'' from others in its genus is the size of its leaves, which at 8–12 mm are substantially smaller than those of ''

Richea scoparia ''Richea scoparia (formerly known as R. angustifolia)'', is a wide spread Tasmanian endemic plant. The genus '' Richea,'' forms part of the Ericaceae (formerly Epacridaceae) family, which are commonly heath-like shrubs. The name refers to the e ...

'' (a species that is often found growing in the same habitat). Its closest relative, ''R. procera'', is found at lower altitudes (over 400m above sea level) but it largely disappears before the sub alpine zone where ''R. sprengelioides'' is most common. These two species do however co-occur at mid altitudes and their resemblance has led some to suggest that they simply represent

clinal variation Cline may refer to: Science * Cline (biology), a measurable gradient in a single trait in a species across its geographical range * Cline (hydrology), a fluid layer with a property that varies * Cline (mathematics) or generalised circle, a circl ...

within the same species . These species can, however, be distinguished by their flowers. ''R. sprengelioides'' has creamy white flowers while those of ''R. procera'' have a pink tip. The most distinct difference between these two species is their filaments, which are white, smooth and slender in ''R. sprengelioides'' as opposed to ''R. procera'' which has yellow, thickened and

papillose This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

filaments. Lastly '' Sprengelia incarnata'', a far more distant relative, looks very similar to ''R. sprengelioides''. The two species may however be distinguished by leaf scars which are visible on the stem of ''R. sprengelioides'' but are absent from that of ''S. incarnata.''

Habitat and distribution

''Richea sprengelioides'' is found throughout the mountainous regions of west, south-west, north-east and the central plateau of Tasmania. It is most common in alpine areas where is most often encountered growing as a small bush within the dominant shrub layer, this, however, does vary with exposure and it can be found growing in a much reduced form within alpine

herbfield Herbfields are plant communities dominated by herbaceous plants, especially forbs and grasses. They are found where climatic conditions do not allow large woody plants to grow, such as in subantarctic and alpine tundra environments. Herbfield is ...

s. At lower altitudes it is sometimes seen growing in exposed rocky sites and less often within well drained woodland. The flowers are sought out and eaten by a number of mammal species.

Diversity and endemism

''Richea sprengelioides'' is one of 11 species within its genus that are endemic to Australia of which 9 are found only in Tasmania. The relative abundance of the genus ''Richea'' within Tasmania raises the question of why there are so few elsewhere. Two theories have been put forward to explain this. Firstly that the Tasmanian species are

paleoendemic Paleoendemism along with neoendemism is a possible subcategory of endemism. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as thro ...

and of Gondwanan origin. This implies that since the breakup of Gondwana conditions elsewhere have become hostile, to the point that Tasmanian species have survived where others have largely died out. A second possibility is that these species are relatively young, having diverged since the breakup of Gondwana. This implies that the genus has as yet been unable to disperse beyond south eastern Australia.

Threats and conservation

''Richea sprengelioides'' is widely found throughout Tasmania and much of its habitat is protected. While this species is not listed by the IUCN, alpine heathland, in which it is most commonly found, has the potential to change rapidly in the coming decades as Tasmania's climate warms. These higher altitude ecosystems contain some of the highest rates of endemism in the Tasmania so changes here are of particular concern.

References

{{Taxonbar, from=Q7330385 sprengelioides Ericales of Australia Flora of Tasmania Endemic flora of Tasmania Plants described in 1810 Taxa named by Robert Brown (botanist, born 1773)