Eucalyptus macrocarpa

''Eucalyptus macrocarpa'', commonly known as mottlecah, is a species of mallee that is endemic to the south-west of Western Australia. It has smooth bark, usually sessile, heart-shaped adult leaves arranged in opposite pairs, large red flowers and broad conical fruit.

Description

''Eucalyptus macrocarpa'' is a mallee that typically grows to a height of , has a sprawling or spreading habit, and forms a lignotuber. It has smooth, shiny, brownish over salmon-pink bark. Its crown is composed of juvenile leaves that are sessile, arranged in opposite pairs, heart-shaped with the bases wrapped around the stem, glaucous, long and wide. The flower buds are glaucous and are arranged singly in leaf axils on a peduncle long and a pedicel up to long. Mature buds are oval, long and wide with a beaked operculum. Flowering occurs from August to January or April or June and the flowers are red, or rarely, creamy white. The fruit is a sessile, woody, broadly conical capsule long and wide with the valves protruding above the rim of the fruit.

Taxonomy and naming

''Eucalyptus macrocarpa'' was first formally described in 1842 by William Jackson Hooker from a specimen collected by James Drummond from the "guangan". The description was published in Hooker's book, ''Icones Plantarum''. In Curtis's Botanical Magazine, Hooker noted " e colour of the flowers is due to the stamens alone; for petals (as in the genus) there are none, and the calyx falls off like the lid of a box". He also noted that "the bright red flowers nestled among the leaves, for a very striking object", and that indigenous people called it "morral".

The specific epithet is derived from the ancient Greek words ''makros'' (μακρός) meaning "long" and ''karpos'' (καρπός) meaning "fruit".Backer, C.A. (1936). ''Verklarend woordenboek der wetenschappelijke namen van de in Nederland en Nederlandsch-Indië in het wild groeiende en in tuinen en parken gekweekte varens en hoogere planten'' (Edition Nicoline van der Sijs). Noongar peoples know the tree as mottlecar.

In 1993, Ian Brooker and Stephen Hopper described two subspecies and the names have been accepted by the Australian Plant Census:
* ''Eucalyptus macrocarpa'' subsp. ''elachantha'' Brooker & Hopper has smaller leaves, buds and fruit than subspecies ''macrocarpa'';
* ''Eucalyptus macrocarpa'' Hook. subsp. ''macrocarpa''. The name ''elachantha'' is derived from the ancient Greek words ''elachys'' meaning "small" and ''anthos'' meaning "flower".

Distribution and habitat

Mottlecah grows in sand in undulating heath between Eneabba, Cataby and Kulin. Subspecies ''elachantha'' has a more restricted distribution south-east of Geraldton.

Conservation status

Subspecies ''macrocarpa'' is classified as "not threatened", but subspecies ''elachantha'' is classified as " Priority Four" by the Government of Western Australia Department of Parks and Wildlife, meaning that is rare or near threatened.

Use in horticulture

''Eucalyptus macrocarpa'' is easily grown from seed, but requires good drainage and a dry, frost-free climate. It was raised from seed in 1842 at Kew Gardens and flowered in 1847.

Image:Eucalyptus macrocarpa x pyriformis KP gnangarra-10.jpg, ''E.macrocarpa x pyrformis''
Image:Curtis's Botanical Magazine, Plate 4333 (Volume 73, 1847).jpg, ''E. macrocarpa'', as figured by Walter Hood Fitch in 1847.

References

{{Taxonbar, from=Q2712369

Eucalypts of Western Australia
macrocarpa
Myrtales of Australia
Mallees (habit)
Plants described in 1842
Taxa named by William Jackson Hooker