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A Diamond-leaf Pittosporum tree on a road in Sydney in late November

Auranticarpa rhombifolia is a rainforest tree of eastern Australia. It is commonly called Diamond Leaf Pittosporum, Holly-leaved Pittosporum, Hollywood, Diamond Leaf Laurel or White Myrtle. The former botanical name is Pittosporum rhombifolium. The tree may grow up to 25 metres in height and a trunk diameter of 45 cm. It is widely planted in many parts of Australia as an ornamental. The white flowers and orange fruit make it an appealing street or garden tree.

The tree flowers in late spring and early summer. The flowers are arranged in an inflorescence known as corymb, a modified raceme in which the lower pedicles are longer than the upper pedicles so that the total inflorescence appears flat-topped.

diagram
Diagram from http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Auranticarpa~rhombifolia

 

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Flower buds of the inflorescence
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Flowers of the inflorescence

Each flower possesses 5 pale green sepals, 1–2 mm long; 5 white petals, 5–6 mm long; 5 stamens; an ovary with 2 carpels.

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A flower under the microscope
The pistil of the flower. The top tip is the stigma.
The pistil of the flower. The top end is the stigma.

The ovary has 2 carpels. Each carpel contains a few large ovules.

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The ovary cut open longitudinally into halves revealing the ovules in the 2 carpels
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The ovary cut open transversely revealing the ovules in the 2 carpels
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The petals and stamens dropped off and the ovaries are growing into young fruits

 

The fruit is at the middle of development. The fruit wall is turning brownish green in colour.
The fruit is at the middle of development. The fruit wall is turning brownish green in colour.
The fruit above is cut transversely open to view the developing seeds. 2 seeds inside this fruit.
The fruit above is cut transversely open to view the developing seeds. This fruit has 2 seeds.
Only one seed is present in this developing fruit
Only one seed is present in this developing fruit

 

Mature fruit is an orange pear shaped capsule, 5 – 10  mm long with two or three oval black seeds.

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Orange pear shaped capsules. (Auranticarpa, which means “gold fruit”)

 

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The mid autumn (April in Sydney), the fruit wall splits open to disperse the seeds. Usually there are 2 seeds in each fruit.

 

 

The bark is grey, irregular, not smooth and almost corky.

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The bark of the tree trunk

Leaves are clustered in pseudo-whorls. Mostly rhomboid or diamond-shaped. Margins irregularly and coarsely toothed in upper half.

Leaf: Rhomboid in shape, 5 to 10 cm long and 4 to 7 cm wide. Midrib, lateral and net veins easily seen on both the upper and lower leaf surface.
Leaf: rhomboid in shape, 5 to 10 cm long and 4 to 7 cm wide. Margins irregularly and coarsely toothed in upper half. Midrib, lateral and net veins easily seen on both the upper and lower leaf surface.

 

 

Acknowledgements :

I would like to thank Ms Seanna McCune, Curator of National Herbarium of New South Wales for her kind support and guidance.

 

Bibliography :

http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Auranticarpa~rhombifolia

https://en.wikipedia.org/wiki/Auranticarpa_rhombifolia

http://www.noosanativeplants.com.au/plants/1453/auranticarpa-rhombifolia-(was-pittosporum-rhombifolium) (drawing)

https://www.youtube.com/watch?v=0Ip1LB5V9e0 (Burke’s Backyard, Pittosporum rhombifolium)(excellent video clip)