Rainforest Tree of the Month, June 2020 – Flindersia species

A recent discussion with friends about a very large tree in their garden which was to have a limb lopped off, has prompted me to feature the species Flindersia as Rainforest Tree of the Month.  The limb of the tree in question hung dangerously over the roof of their house.   My friends understood this tree to be Australian Teak, Flindersia australis, but I questioned this as it did not quite match the characteristics of Flindersia australis.

The seed capsule collected from my friends’ tree, was still green and had a bumpy surface rather than the characteristic spiny surfaced, five valved seed capsules of the Flindersia australis.   Nor did the leaflets of the compound leaves, being slightly curved, match the elliptic shape of those of Flindersia australis.  The distribution of this tree is in rainforest from near Proserpine to northern NSW, at altitudes up to 750 metres.   So, I feel that more likely candidates for my friends’ tree would be Flindersia acuminata, Flindersia brayleana, Flindersia bourjotiana or Flindersia pimenteliana, all of which are endemic to Paluma.

There are seventeen species of Flindersia world-wide; growing in New Caledonia, New Guinea, Malesia and Australia. Fifteen species are endemic to Australia.  The species is named after Matthew Flinders (1774-1814), the renowned navigator and cartographer who led the voyage of ‘The Investigator’ on which the British botanist, Robert Brown, collected many Australian plants.  Flindersias are members of the Rutaceae family.

Flindersia australis, also known as Teak, Australian Teak and Crows Ash,can grow to a height of 40 metres on rich, volcanic rainforest soil.  It is somewhat smaller elsewhere.  Sprays of tiny white flowers appear from August to February with the spiny seed capsules forming from March to January. Unlike most other Flindersia species, these segments do not separate into individual portions.  The 35-50mm seeds are flattish and winged at the apex.  The timber is in demand for general building, flooring and fencing.  It has a high oil content and is readily flammable.

Flindersia pimenteliana is also known as Maple Silkwood, Rose Silkwood and Mountain Silkwood.  This majestic tree grows to 30 metres high and may be buttressed.  It occurs from Mt Finnegan near Cooktown to Paluma and also is found in New Guinea.  The leaves, like other Flindersias, are compound but the leaflets taper to a narrow point.  The flowers are similar in size to the inflorescence of the other Flindersia species but are red to purple.  They appear from November to March and are difficult to see high in the canopy.  The fruiting capsule, 55 – 115 mm long, is green to brown with five spiny valves.  These split and release about 20 flat, winged seeds about 45-50mm long, from July to December.

Sulphur-crested cockatoos eat the seeds.

The timber of this tree was once used to make barrels and very decorative cabinet timber.  Although young plants grow readily, they are not an economic tree to grow in plantations due to their spreading structure.   Leaf material has been found to be active against some tumours.

There are several fine examples of Flindersia pimenteliana to be seen around the village. The easiest to find is in the stand of trees in the area between the tree ferns and the road cutting opposite the Rainforest Inn, (the kitchen end near the entrance to the motel units).   Some still attached, green seed capsules hang just above eye level.  Other trees can be seen at the end of Smith Crescent, at Number 20 and at the fence-line between Numbers 15 and 17 Mount Spec Road.

Flindersia schottiana is another tree which could possibly be found in the Paluma area as its distribution range is from Cape York to Port Macquarie at altitudes up to 1300 metres.  This tree is also known as Silver Ash, Bumpy Ash, Floppy-leaf Ash and Cudgerie. A majestic tree, growing to 45 metres, it is rarely buttressed.    The trunk features large bumps where old branches have been detached, hence its common name, Bumpy Ash.  The tree has compound leaves with 7 to 9 leaflets, 50 to 260mm long.  The upper-side of the leaves is mildly hairy with dense, fine hairs on the under-side.  The tiny white or cream flowers are fragrant, appearing from August to December and in May. The five-valved fruit capsules are spiny, 80-130mm and release about 30 flat winged seeds from December to April.  Flindersia schottiana is a pioneer tree, often found in regrowth areas and rainforest margins.

Flindersia acuminata, also known as Silver Maple, Silver Silkwood, White Silkwood and Ice-wood, occurs at altitudes up to 1200 metres in rainforests between the Windsor Tableland and Paluma.  The tree can grow to a height of 40 metres and may be buttressed.  The elliptic leaflets of the compound leaves are from 50 to 150 mm long, slightly curved, and tapering to a point.  Fragrant white or cream flowers grow in terminal or axillary panicles from November to January.  They are tiny, with five petals and are only about 3 mm in size. The fruit capsules, appearing from June to March are green to brown, 90 to 150 mm long and have five spiny valves which split to release flat, papery winged seeds, 65 to 80 mm.

Flindersia bourjotiana, also known as Queensland Silver Ash, Silver Ash and White Ash. The distribution of this tree is in rainforests from McIvor River near Cooktown to the Paluma Range at altitudes up to 1200 metres.  The tree grows to about 35 metres and may be buttressed.  The leaves are compound, with 3 to 9 elliptic leaflets, from 50 to 190 mm long.  The underside of leaves can be slightly hairy.   The tiny, (5-9mm), fragrant flowers can be white, cream or green and grow in terminal or axillary panicles, or sprays. Flowering occurs between April and January.  Fruit capsules can be up to 150 mm long with five spiny valves which split to release several flat, winged seeds, 30-70 mm long.  Sulphur-crested cockatoos and giant white-tailed rats eat the seeds.

Flindersia brayleana, is also known as Queensland Maple, Maple Silkwood and Red Beech. A tree growing to 35 metres, its distribution is from the Windsor Table-land to Mount Halifax near Townsville, at altitudes up to 1150 metres.  The compound leaves have slightly curved leaflets, tending toward an ovate/elliptic shape and ranging from 60 to 210 mm in length.  Tiny fragrant white flowers with five petals 3mm in size grow in terminal or axillary panicles from November to January.  They are difficult to see high in the canopy.  The fruit capsules, are 60 to 100 mm long, and have bumps rather than spines on the surface.  They split into five valves, or segments, and release several winged seeds.  Flindersia  brayleana was once a common tree in rich, red, volcanic soils on the Table-land and on Mount Spec however, high demand for its exceptionally beautiful pink timber has caused it to become scarce. During World War 2, the timber was sought for use in aircraft production, such as in the manufacture of propellers and for ply-wood used in the Mosquito bomber aircraft.  The timber was also used in rifle stocks and for beautiful decorated stocks in sporting rifles and shotguns. Boxes, barrels and window frames were also made from this timber.  The timber can cause dermatitis.

Text and Photos by Colwyn Campbell