Grewia graniticola

granite emu bush


Grewia graniticola

Halford 1993

pronounced: GROO-ee-ih gran-it-ih-KOH-luh

(Malvaceae — the hibiscus family)


common name: granite emu bush

native 4Grewia is named for Nehemiah Grew (1641–1712), English philosopher, physician and botanist. In 1682 he published his great work, The Anatomy of Plants. It was divided into 4 books, Anatomy of Vegetables begun, Anatomy of Roots, Anatomy of Trunks, and Anatomy of Leaves, Flowers, Fruits and Seeds. The book was illustrated with 82 plates. Linnaeus thought highly of his work, and named this genus in his honour. Graniticola means ‘granite-dweller’.

This plant is classed as ‘rare’, Magnetic Island being one of its few strongholds. Cape Gloucester, near Airlie Beach, is one of the very few mainland regions where the plant is found, and it is also found on the nearby Gloucester Island.

This is a small spreading shrub that can grow up to about 1 m in height. The leaves are distichous, that is to say, arranged alternately in two rows in the same plane on opposite sides of the stem. The leaves measure about 4 – 8 cm by 3 – 4 cm, and have irregularly serrate margins. Their undersides are densely, greyish-white stellate pubescent.

The plant is monoecious. The yellowish-green flowers occur in small clusters in the leaf axils, and are 1 cm or a little more in diameter, usually with 4 sepals and smaller petals. The male flowers have 8 – 12  stamens, and the female flowers 2 – 4 staminodes and a lobed stigma.

The fruit is a slightly fleshy drupe, with up to 4 lobes, stellate pubescent on the outside.

The plant is found in open eucalyptus woodland, or in landscape dominated by hoop pines (Araucaria cunninghamii), amongst spinifex (Triodia stenostachya), or in open patches in vine thickets. It is often found growing round the base of a granite boulder. The plants photographed were by the side of the track leading to the Forts. After fire, the plant will usually recover by sprouting from buds below the soil. Although the plant is reasonably common on Magnetic Island, the scarcity of locations where it is found elsewhere means that it may well become vulnerable to competition from such plants as rubber vine (Cryptostegia grandiflora) and lantana (Lantana camera), and may also affected by the construction of tracks, roads and power lines.


Photographs taken on the Forts walk, 2014
Page last updated 9th January 2019