Isopogon Trilobus

''Isopogon trilobus'', commonly known as barrel coneflower, is a species of flowering plant in the family Proteaceae and is endemic to South Coast Western Australia. It is a shrub with wedge-shaped leaves with lobed or toothed margins, and oval, spherical or barrel-shaped heads of cream-coloured to yellow flowers.

Description

''Isopogon trilobus'' grows as a shrub anywhere from in height. The new stems are pale to reddish brown, and initially covered with small fine hairs before becoming smooth. The leaves are long and have three to nine teeth or three to five lobes deep lobes, the teeth or lobes with a sharp point on the end. The flowers are arranged on the ends of branchlets in sessile, oval, spherical or barrel-shaped heads wide with hairy, broadly egg-shaped involucral bracts at the base. The flowers are silky-hairy, cream-coloured to yellow, and long. Flowering occurs from September to December and the fruit is a hairy oval nut, fused with others in a barrel-shaped head about in diameter.

Taxonomy

''Isopogon trilobus'' was first formally described in 1810 by botanist Robert Brown in Transactions of the Linnean Society. ''Isopogon tripartitus'' R.Br., that Brown described in 1830 in the '' Supplementum'' to his '' Prodromus Florae Novae Hollandiae et Insulae Van Diemen'', is now considered a synonym of the older name.
The specific epithet (''trilobus'') is derived from the Latin ''tri-'' "three", and ''lobus'' "lobe", and relates to the leaves. The epithet ''tripartitus'' means "divided into three parts".

Distribution and habitat

Barrel coneflower is widespread from the Stirling Range east to Israelite Bay along the south coast of Western Australia where it grows on sandplains, dunes or rocky outcrops, on sandy soils, sometimes over laterite, in heathland or shrubland communities.

Ecology

The colletid bee ''Hylaeus sanguinipictus'' and halictid bee ''Lasioglossum caesium'' have been recorded visiting the flowerheads of ''Isopogon trilobus''.

Use in horticulture

Sensitive to '' Phytophthora cinnamomi'' dieback, ''I. trilobus'' requires excellent drainage and full sun. It will likely not tolerate humid climates. Grafting onto eastern species such as '' I.anethifolius'' or '' I.dawsonii'' could render it more adaptable to a wider climatic range. Its dense habit and large fruit give it its horticultural potential.

References

{{Taxonbar, from=Q6086251

trilobus
Eudicots of Western Australia
Endemic flora of Western Australia
Taxa named by Robert Brown (botanist, born 1773)
Plants described in 1810