Conospermum caeruleum

Conospermum caeruleum, commonly known as blue brother, is a species of flowering plant in the family Proteaceae and is endemic to the south west of Western Australia. It is a prostrate shrub with small, dense heads of blue, rarely pink flowers and usually grows in heavy soils subject to flooding.

Blue brother
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Proteales
Family:	Proteaceae
Genus:	Conospermum
Species:	C. caeruleum
Binomial name
Conospermum caeruleum R.Br.[1]
Synonyms[1]
Connospermum coeruleum B.D.Jacks. orth. var.

Description

It grows as a prostrate or straggly shrub usually growing to a height of about 0.5–1.0 metre (2–3 ft) and a spread of up to 2 metres (7 ft). The leaves are clustered at the base of the stem, have a stalk 5–60 millimetres (0.2–2 in) and a leaf blade that is thread-like to egg-shaped and 14–148 millimetres (0.6–6 in). The leaves have prominent veins and end abruptly in a sharp point. The flowers are arranged in dense clusters of up to 18 tube-like blue flowers, each about 5–8 millimetres (0.2–0.3 in) long. Flowers appear between July and October and are followed by the fruit which is a nut about 2 millimetres (0.08 in) long and 2–2.5 millimetres (0.08–0.1 in) wide.^[2][3][4]

Taxonomy

Conospermum caeruleum was first formally described in 1810 by Robert Brown and the description was published in Transactions of the Linnean Society of London from a specimen collected near "King George's Sound, west coast of New Holland".^[5][6] The specific epithet (caeruleum) is a Latin word meaning "sky-blue".^[7]

Six subspecies are recognised by the Australian Plant Census as at November 2020:

• Conospermum caeruleum R.Br. subsp. caeruleum^[8]
• Conospermum caeruleum subsp. contortum E.M.Benn.^[9]
• Conospermum caeruleum subsp. debile (Kippist ex Meisn.) E.M.Benn.^[10]
• Conospermum caeruleum subsp. marginatum (Meisn.) E.M.Benn.^[11]
• Conospermum caeruleum subsp. oblanceolatum E.M.Benn.^[12]
• Conospermum caeruleum subsp. spathulatum Benth. E.M.Benn.^[13]

Distribution and habitat

Conospermum caeruleum occurs from Busselton to east of Albany^[2] in the Avon Wheatbelt, Esperance, Geraldton Sandplains, Jarrah Forest, Mallee, Swan Coastal Plain and Warren biogeographical regions of Western Australia^[14] growing on sand, sandy peat, stony clay, laterite or granite in areas that are wet in winter.^[15]

Use in horticulture

Conospermum species, especially the Western Australian ones are difficult to cultivate.^[16]

Conservation status

Conospermum caeruleum is classified as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.^[14]

Gallery

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  C. caeruleum subsp.caeruleum
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  C. caeruleum subsp.caeruleum