White Oak

Grevillea baileyana
Tree
Alternate
Simple
Cream
Green

Grevillea baileyana is a medium to large tree, usually to about 10 metres but occasionally to 30 metres high. Bark is grey, hard and sometimes scaly. Leaves are rich green with the underside of the new growth having a rusty or bronze sheen. This is a particularly useful diagnostic point in the growing period. Juvenile leaves have 5-9 broad lobes but adult leaves are simple, glabrous above and finely silky beneath.

Common names 
Also known as: brown silky oak , Scrub Beefwood, Findlay's Silky, Bailey's Silky Oak, Findlay's Silky Oak,
Family 
Proteaceae
Deciduous 
No
Flowering time 
Late spring and early summer
Native/Exotic 
Native
Origin 
White Oak is native to north-eastern Queensland and the southern coastal regions of Papua New Guinea. In Queensland it is restricted to two main areas, from the McIlwraith Range to the vicinity of Coen and from Cooktown south to Ingham.
Notifiable 
No
State declaration 
Nil
Council declaration 
NIL - Reduce
Known distribution 

Occurs in CYP and NEQ. Altitudinal range from sea level to 900 m. Grows in well developed lowland rain forest, gallery forest and drier, more seasonal rain forest. there are reports of young. Plants are reportedly becoming established in bushland in the Brisbane and Sunshine Coast areas. Several seedlings and saplings have been reported from conservation reserves in Kuraby, Larapinta and Tingalpa in Brisbane. Numerous young plants have also been recorded becoming established in the vicinity of mature adult trees in the Tewantin and Noosaville areas on the Sunshine Coast.This species is favoured by disturbance and is a characteristic species of regrowth in the area of its occurrence.

Habitat 

White oak favours wetter habitats in south-eastern Queensland (i.e. disturbed rainforests, wet sclerophyll forests and tea tree swamps)

Habit 

A tree growing up to 30 m tall, but usually less than 10 m in height in cultivation. Its trunk and older branches have grey bark while its younger stems and new growth is covered in rusty brown hairs. 

Impact and control methods 

White Oak is favoured by disturbance and is a characteristic species of regrowth areas within its native range. Hence, it is probably well adapted to colonising areas of disturbed forest outside its native range. Evidence from this very early stage of invasion suggests that it favours wetter habitats in south-eastern Queensland (i.e. disturbed rainforests, wet sclerophyll forests and tea tree swamps). In some cases plants have become established hundreds of metres away from cultivated specimens, in undisturbed natural vegetation.

Stem and leaves 

The alternately arranged leaves are variously shaped depending on the age of the plant. Leaves of younger plants and regrowth are usually quite large (up to 30 cm long) with 5-9 prominent lobes (each 3-11 cm long and 15-30 mm wide). Leaves of seedlings and adult plants are usually smaller (10-20 cm long and 1-6 cm wide), and are either entire or have a few small lobes towards their tips. The upper leaf surfaces are dark green while the lower surfaces are distinctly rusty brown. Mature leaves rusty brown on the underside. Young leafy twigs rusty brown. Lateral veins forming loops (sometimes a double series of loops) inside the blade margin.

Flowers and fruits 

The white flowers are borne in elongated clusters at the tips of the branches have a strong nectar perfume which attracts myriad insects to the flower head in late spring and early summer. These clusters (6-14 cm long) are cream in colour and usually held upright. Each cluster contains numerous small, densely packed, flowers which have inconspicuous petals and a very conspicuous style ending in a swollen stigma. 

The small fruit (12-19 mm long and 7-9 mm wide) turns from green to brown as it matures and splits open when fully mature to release a single papery seed (11-12 mm long and 6-7 mm wide)

Reproduction and dispersal 

This species reproduces only by seeds, which are primarily wind-dispersed. However, seeds may also be spread in dumped garden waste

Similar species 

White Oak can be confused with White Silky Oak (Grevillea hilliana), Ivory Curl (Buckinghamia celsissima) and other closely related members of the Proteaceae. However, White Oak can be easily distinguished from these species by its rusty brown leaf undersides. The flower clusters of Ivory Curl are also drooping in nature, instead of being held upright.