The bootlace oak (Hakea lorea) grows as a tree or shrub and is recognised by its unusually long, narrow leaves. At up to 68 centimetres long but just 0.2 centimetres wide (1) (2) (3), these distinctive leaves give the bootlace oak its scientific name, lorea, which comes from a Latin word meaning ‘made from long strips of leather’ (1) (4).
The leaves of the bootlace oak grow at alternating points along the plant’s stems (1), and are smooth and more or less cylindrical, tapering at the ends (1) (3). Although usually undivided (3), the leaves of this species may sometimes comprise two to six spreading segments that grow from a long, undivided base (2). The bark of the bootlace oak is dark grey (3), and like several other Hakea species this tree is sometimes referred to as a ‘corkwood’ as its bark is deeply furrowed and cork-like (2) (3).
The flowers of the bootlace oak are white to yellow or greenish, and grow in large, hanging clusters known as inflorescences (1) (2) (3). Each inflorescence may contain up to 200 individual flowers (2) (3), with each flower measuring up to about 1.3 centimetres long (1) and growing on a short stalk (1) (2) (3).
The bootlace oak produces numerous small, woody, reddish-brown fruits which measure up to 6 centimetres by 2.8 centimetres (1) and consist of 2 roughly oval valves (2) (3). The fruits open to release two seeds (3), and each seed has a wing down one of its sides (1) (2) (3).
There is some variation in the appearance of the bootlace oak across its range, and two subspecies are generally recognised: Hakea lorea lorea, and Hakea lorea borealis, which usually has slightly larger fruits and flowers (1) (2). H. l. lorea typically has slightly larger leaves than H. l. borealis (1), but there is some overlap in all these characters (2).
- Also known as
- bootlace tree, cork tree, corkwood, witinti.
- Grevillea lorea, Hakea cunninghamii, Hakea lorea var. mollis, Hakea suberea.
- Height: up to 10 m (1) (2) (3)
Bootlace oak biology
The bootlace oak usually flowers between February and September, with the subspecies H. l. lorea flowering slightly later, from April to September (1) (2). The flowers of this species are hermaphroditic, containing both male and female reproductive parts. Although little other specific information is available on the biology of this tree, other Hakea species are known to be pollinated by insects, birds, or sometimes even by small marsupials (1).
Like many other Hakea species, the bootlace oak is adapted to cope with fires. This species possesses an underground swelling known as a ‘lignotuber’ (2) (3), which allows the plant to regrow from the base after a fire (3). In addition, its woody fruits remain on the plant for some time (1) (3), only opening after the branches that support them die. The woody fruit protects the seeds during a fire, and the fruit opens soon after, releasing the seeds. Fire can therefore cause large numbers of seeds to be released, and the seeds of Hakea species usually then germinate within a month (3).
Bootlace oak range
The bootlace oak is native to Australia, where it is widespread over northern and central parts of the continent (2) (3). This species occurs from Western Australia east to Queensland, and south to north-western South Australia (2). It is rare in New South Wales (3).
As suggested by its scientific name, borealis, which means ‘northern’, the subspecies H. l. borealis is restricted to northern parts of the species’ range, in the Kimberley region of Western Australia and in northern parts of the Northern Territory (1) (2).
Bootlace oak habitat
The bootlace oak typically occurs in sclerophyll shrubland, mixed woodland or grassland, and grows in a range of soil types, including sandy, clayey, rocky and stony soils (1) (2). This species can often be found on floodplains or on rocky outcrops in sand plains (1).
Bootlace oak status
The bootlace oak has yet to be classified by the IUCN.
Bootlace oak threats
Very little information is available on the status of the bootlace oak population, or on the potential threats to this species. However, in Western Australia the bootlace oak is not reported to be threatened (1).
Bootlace oak conservation
There are no specific conservation measures currently known to be in place for the bootlace oak.
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- To begin to grow, usually following a period of dormancy and in response to favourable conditions. For example, the sprouting of a seedling from a seed.
- Possessing both male and female sex organs.
- The reproductive shoot of a plant, which bears a group or cluster of flowers.
- A diverse group of mammals characterised by their reproduction, in which gestation is very short, and the female typically has a pouch (marsupium) in which the young are raised. When born, the tiny young crawls to the mother’s teats, where it attaches and stays for a variable amount of time, while it continues to develop. Marsupials also differ from placental mammals in their dentition.
- To transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
- A type of vegetation with hard, thick-skinned leaves; for example, eucalypts and acacias.
- A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.