Gastrolobium melanopetalum is a shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 in the family Fabaceae

Fabaceae

The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...

 which is endemic

Endemic (ecology)

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 to the south-west

Southwest Australia

Southwest Australia is a biodiversity hotspot that includes the Mediterranean forests, woodlands, and scrub ecoregions of Western Australia. The region has a wet-winter, dry-summer Mediterranean climate, one of five such regions in the world...

 of Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

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Description

The species is a shrub up to 3 metres in height. It has narrow-ovate leaves which are 1.4 to 6 cm long and 0.4 to 2 cm in length. Distinctive purple-black pendulous pea-flowers are produced from early spring to early summer (September to December in Australia). It is not known whether this species shares the toxic properties of many other members of the genus Gastrolobium

Gastrolobium

Gastrolobium is a genus of flowering plants in the family Fabaceae. There are over 100 species in this genus, and all but two are native to the south west region of Western Australia....

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Taxonomy

The species was first formally described in 1864 by botanist Ferdinand von Mueller

Ferdinand von Mueller

Baron Sir Ferdinand Jacob Heinrich von Mueller, KCMG was a German-Australian physician, geographer, and most notably, a botanist.-Early life:...

 in Fragmenta Phytographiae Australiae

Fragmenta phytographiae Australiae

Fragmenta phytographiae Australiae is a series of papers authored by the Victorian Government botanist Ferdinand von Mueller in which he published many of his approximately 2000 descriptions of new taxa of Australian plants. The papers were issued in 94 parts between 1858 and 1882 and published in...

. He gave it the name Brachysema melanopetalum, the specific epithet being derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 words melanos (black) and petalon, alluding to the dark-coloured flowers. In 1995, botanist Michael Crisp placed the species in the genus Gastrolobium along with a number of other Brachysema species.

Distribution

This species is usually found in thickets growing near streams or freshwater swamps. It occurs south of Perth

Perth, Western Australia

Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....

 between the Darling Scarp

Darling Scarp

The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north-south to the east of the Swan Coastal Plain and Perth, Western Australia...

 and the Blackwood River

Blackwood River

The Blackwood River is a major river and catchment in the South West of Western Australia.The river begins at the junction of Arthur River and Balgarup River near Quelarup and travels in a south westerly direction through the town of Bridgetown then through Nannup until it discharges into the...

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