Queensland Tree Waratah

Appearance

In nature, this is a rainforest tree that can reach 33 m in height with a diameter at breast height of 0.6 m, although in cultivation 10 m is more likely. The trunk has light grey bark with brown lenticels. New branchlets and leaves are hairy. The green foliage consists of several distinct juvenile and adult leaf forms, which are arranged alternately along the stems. Very young plants begin with their first two to four leaves having two or three lobes, but then have narrow elliptic leaves with entire margins, measuring 6.5 to 18 cm long and 1.3–2.2 cm wide. These are then succeeded by pinnate juvenile leaves that have two to nine lobes arising at 30 to 40 degrees forwards, and reach 50 cm long. They have prominent midveins along the midline of the main leaf and the lobes. The elliptic or obovate adult leaves are 8–25 cm long and up to 4.5 cm wide, and sit on 1.5 to 2.5 cm long petioles.

Occurring in spring, the bright red or orange-red inflorescences are terminal and well displayed, and consist of anywhere from 10 to 52 individual flowers split into smaller groups of 2 to 20 flowers, arranged in a corymb. The flowers sit atop stalks up to 3.5 cm in length, which arise in pairs off main horizontal stalks within the inflorescence. Each flower consists of a tubular perianth up to 4 cm long, which partly splits along one side at anthesis to release the thick style. The stigma is contained within a slanting disc-like structure at the tip of the style. The tubular perianth splits into four segments at its tip, and the anther lies in the concave parts within each of these segments. The pedicel and the outer surface of the perianth are pubescent. Flowers are followed by woody rectangular seed pods that sit on long stalks, and are 7–10 cm long. Each pod contains 8 to 10 seeds, and is ripe in February and March. Each seed is separated from the others by a membranous separator, and has a long rectangular wing, which is much longer than the seed itself. The seedlings have obovate cotyledons that are 0.8–1 cm wide by 1 cm long.

"Alloxylon flammeum" can be distinguished from the co-occurring "Alloxylon wickhamii" by its hairy stems and petioles. It also has brighter flowers than the latter species. The New Guinean species "A. brachycarpum" resembles "A. flammeum" but has duller flowers, leaves that are shorter and wider, and fewer hairs on its perianth. "A. pinnatum" has pinnate adult leaves and larger inflorescences made up of 50 to 140 individual flowers. It also has crimson pollen rather than the yellow of "A. flammeum".

Distribution

A plant of the Wet Tropics bioregion, "Alloxylon flammeum" is found on the Atherton Tablelands in Far North Queensland at altitudes of 700 to 820 m above sea level. Its range is from Danbulla to the upper Barron River, though most of its rainforest habitat has been cleared for agriculture, and it is found in protected remnants such as Mount Hypipamee National Park, Danbulla National Park, Crater Lakes National Park, Curtain Fig Tree National Park, and Hallorans Hill Conservation Park. Found on basalt- or granite-based soil, it is a component of complex notophyll vine forest or rainforest, where it is a canopy or emergent tree. This forest, also known as Mabi forest, has an uneven canopy layer to around 45 m and significant scrub understory. Here "Alloxylon flammeum" is found with such species as candlenut, "Argyrodendron" spp., fishtail lawyer cane, rose maple, shining-leaved stinging tree, fig trees, Queensland maple, cabbage crowsfoot, northern brush mahogany, Atherton turkey bush, and red cedar.

Status

"Alloxylon flammeum" is listed nationally as "vulnerable" under the Australian Environment Protection and Biodiversity Conservation Act 1999, which indicates that there is a high risk it will become extinct in the wild in the mid-term future. Before the establishment of the EPBC Act, it was, and currently remains, listed as "vulnerable" under the state-based Nature Conservation Act 1992. Furthermore, it was listed by the International Union for Conservation of Nature in 1997. Most of its habitat has been cleared for agriculture and development. Remaining stands in protected areas are highly fragmented. Furthermore, plants in cultivation are likely to come from a limited genetic pool. With under 2% of its original extent remaining, the rainforest is threatened by invasive plants and grazing by feral and domestic animals.

Habitat

A plant of the Wet Tropics bioregion, "Alloxylon flammeum" is found on the Atherton Tablelands in Far North Queensland at altitudes of 700 to 820 m above sea level. Its range is from Danbulla to the upper Barron River, though most of its rainforest habitat has been cleared for agriculture, and it is found in protected remnants such as Mount Hypipamee National Park, Danbulla National Park, Crater Lakes National Park, Curtain Fig Tree National Park, and Hallorans Hill Conservation Park. Found on basalt- or granite-based soil, it is a component of complex notophyll vine forest or rainforest, where it is a canopy or emergent tree. This forest, also known as Mabi forest, has an uneven canopy layer to around 45 m and significant scrub understory. Here "Alloxylon flammeum" is found with such species as candlenut, "Argyrodendron" spp., fishtail lawyer cane, rose maple, shining-leaved stinging tree, fig trees, Queensland maple, cabbage crowsfoot, northern brush mahogany, Atherton turkey bush, and red cedar.