''Tribulus platypterus'', the cork hopbush, is a species of

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

Zygophyllaceae Zygophyllaceae is a family of flowering plants that contains the bean-caper and caltrop. The family includes around 285 species in 22 genera. Plants in the family Zygophyllaceae may be trees, shrubs, or herbs. They are often found in dry habita ...

, which is endemic to the northwest of

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It is closely related to ''Tribulus suberosus''. It was first described by

George Bentham 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 studi ...

in 1863 from a specimen collected by

Francis Thomas Gregory Francis Thomas "Frank" Gregory (19 October 1821 – 23 October 1888) was an Australian explorer and politician. Born in England, he emigrated with his family to Australia as a boy. He was the younger brother of the explorer and politician Augu ...

in the Hammersley Ranges. An isosyntype (MEL 79454) collected by Gregory (east of the Hammersley Ranges) is held in the

National Herbarium of Victoria The National Herbarium of Victoria ( Index Herbariorum code: MEL) is one of Australia's earliest herbaria and the oldest scientific institution in Victoria. Its 1.5 million specimens of preserved plants, fungi and algae—collectively known a ...

. The specific epithet, ''platypterus'', is derived from two Greek roots/words, ''platy-'' ("broad") and ''-pterus'', ("winged"), and describes the plant as having "broad-winged" fruit.

Description

''Tribulus platypterus'' is a spreading upright shrub which grows to a heights from 40 to 100 cm high and spreading from 50 to 200 cm. The stems usually lack corky bark except at the plant base. The leaves occur in unequal pairs, and have from 4–7 pairs of leaflets on a stalk which is 3–13 mm long. Within each compound leaf the leaflets have short stalks and vary 4–23 mm long by 2.2–8.3 mm wide. The flower stalk is upright and 3.5–6.5 mm long. The sepals are 6–8.5 mm long, and have no covering or have sparse silky hairs on the upper surface, and densely hairy on the lower surface. The petals are elliptic, 10–11 mm long, and not hairy. There are 10 stamens, which may all be fertile or some or all them may be shorter and staminodal. The longer filaments are 5.5–6 mm long; and the shorter filaments are about 3 mm long. The ovary is moderately to densely covered with white silky hairs, and has one ovule per cell. Both the style and stigma are 4.5–6 mm long. The fruit is a ball-shaped 5-winged schizocarp (a fruit which splits into individual carpels), the wings of which give rise to the specific epithet of "broad winged", and is 12–18 mm long by 15–21 mm wide. It mostly flowers from August to October.

Distribution & habitat

It is found in the

IBRA Regions The Interim Biogeographic Regionalisation for Australia (IBRA) is a biogeographic regionalisation of Australia developed by the Australian government's Department of Sustainability, Environment, Water, Population, and Communities. It was devel ...

of the

Central Kimberley The Central Kimberley, an interim Australian bioregion, is located in the central Kimberley region of Western Australia, comprising an area of .

, the

Gascoyne The Gascoyne region is one of the nine administrative regions of Western Australia. It is located in the northwest of Western Australia, and consists of the local government areas of Carnarvon, Exmouth, Shark Bay and Upper Gascoyne. The Gasc ...

, the

Little Sandy Desert The Little Sandy Desert (LSD) is a desert region in the state of Western Australia, lying to the east of the Pilbara and north of the Gascoyne regions. It is part of the Western Desert cultural region, and was declared an interim Australian ...

, the Murchison, and the

Pilbara The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a glo ...

, in rocky areas, including creek banks and beds, and often in sand.

Conservation status

Under West Australian conservation laws it is deemed to be "not threatened".

References

External links

''Tribulus platypterus'' (images from Flickr)
{{Taxonbar, from=Q18077538 Plants described in 1863 Flora of Western Australia platypterus