Grevillea robusta A.Cunn. ex R.Br.

Silkoak (en), Grévillée robuste (fr)

Species

Angiosperms > Proteales > Proteaceae > Grevillea

Characteristics

Handsome tree, 10-25(-40) m, with robust trunk when old; bark greyish-brown, rugged, fissured; young branches rusty-tomentose. Leaves pinnate with about (4-) 10-20 pinnatifid pinnae, fern-like, the secondary lobes or segments entire or again lobed, lanceolate or rarely linear, terminal one mostly longer than 2.5 cm, margins recurved, upper surface glabrous or sprinkled with appressed hairs and obscurely veined, undersurface brown-ish-, later whitish-silky; the whole leaf 15-20 cm long and nearly as wide, the 1.8-7 cm long petiole included. Racemes secund, many-flowered, 7-12 cm, solitary or short-paniculate on very short, leafless, tomentulose branches on the old wood; rhachis stoutish, glabrous. Pedicels slender, c. 1 cm long, glabrous. Perianth glabrous in-and outside, tube c. 6-9 mm, scarcely dilated at the base, revolute under the 3 mm ovoid limb, orange to golden-yellow or golden-brown in colour. Torus slightly oblique. Disk prominent, semi-annular. Ovary glabrous, stipitate; style c. 1.5 cm, the stigmatic disk somewhat oblique with a central cone. Fruit broad, very oblique, boat-shaped, pointed, ± 1.5 cm long. Seeds winged all round.
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Tree to c. 15 m tall, with dark greyish bark. Shoots and lvs reddish brown-tomentose when young, soon becoming grey. Lvs pinnate and fern-like, to c. 30 cm long (including petiole 2-6 cm long); rachis and petiole greyish tomentose with some reddish brown hairs; pinnae (8)-12-c. 20 cm long, deep green and glabrate on upper surface, with greyish white appressed tomentum on lower surface (sparsely hairy and green in juvenile stage), entire and linear to lanceolate or pinnatisect with 1-4 narrow to broadly triangular lobes (narrower in juvenile lvs); apex of entire pinnae and lobes of pinnatisect pinnae acute or mucronate. Infl. a secund, racemose panicle, 10-16 cm long, glabrous except for lower part of rachis. Pedicels 1.3-2 cm long, filiform. Perianth 9-12 mm long, orange or yellow-orange; limb ± ellipsoid, soon revolute under tube. Nectary lobed. Ovary glabrous; stipe c. 3 mm long. Style c. 2 cm long, with a small somewhat oblique cone at apex. Fr. 1.5-2 cm long, very oblique. Seed winged all round.
Tree 8-40 m tall. Leaves 10-34 cm long, 90-150 mm wide, deeply dissected with 11-24 (-31) primary lobes, these entire to 5-partite, sometimes with tertiary division; ultimate lobes oblong to elliptic or subtriangular, 0.5-5 cm long, 2-10 mm wide; margins shortly recurved; lower surface subsericeous to subvillous. Conflorescence erect, terminal, simple to 4-branched; unit conflorescence secund, 12-16 cm long, many-flowered, acropetal. Flowers acroscopic; pedicels 7.5-16 mm long; torus oblique. Flower colour: perianth golden yellow to orange (rarely reddish) outside, inside (partially exposed) with red blotches; style yellow-orange. Perianth glabrous inside and out. Pistil 21-29 mm long, glabrous; ovary stipitate; pollen-presenter erect, shortly conical. Follicle laterally compressed, ellipsoidal to ovoid, 12-16 mm long, glabrous.
A small to large evergreen tree. It grows to 30 m high. It can spread to 4-10 m wide. It is cone shaped. The branches have a brown rusty covering. The leaf stalk is 1.5-7 cm long. The leaves are feather like. There are 7-15 segments and these segments are sword like and 15 mm wide. The leaf blade is 15-25 cm long by 7-15 cm wide. The edges can be curved back. They are silvery on the underside. The flowers occur as masses of long golden yellow blooms. The flower stalk is slender and 1-1.4 cm long. The fruit are boat shaped and 1.5 cm long by 7 mm wide. There are 2 seeds. The seeds are black. They have wings.
Tree up to 30 m. high.. Leaves up to 35 cm. long, pinnate with up to 22 alternate or subopposite pinnae, the pinnae with 1-several linear or linear-oblong acute lobes to deeply pinnatifid or pinnate with up to 16 lobes or pinnules, glabrous above, closely appressed pubescent beneath.. Inflorescence with main axis up to 24 cm. long, usually with several simple lateral branches from near the base, appressed pubescent towards the base but glabrous distally; pedicels 9-15 mm. long, glabrous.. Perianth 7-10 mm., glabrous, bright yellow to orange or reddish.. Fruits ±15 ×10 mm., blackish, glabrous.
Evergreen tree, 18-35 m high, shoots slightly hairy when young, glabrous later. Leaves pinnately divided, 150-300 mm long, dark green above, greyish white beneath, leaflet margins recurved. Inflorescence terminal racemes, 80-150 mm long. Flowers pedicellate; perianth lobes 20-30 mm long, golden-orange. Flowering time Sept.-Nov. Fruit a leathery follicle, brownish black.
A tall tree up to 35 m. Leaves to 300 mm long, green above, with grey, silky hairs below, pinnately divided. Flowerhead a toothbrush-like raceme up to 120 mm long, orange, in clusters on short branchlets. Flowers with a 10 mm long stalk, producing copious nectar. Perianth 6 mm long. Style 20 mm long. Flowers: All year.
Leaves up to 35 cm long, pinnate with up to 22 alternate or subopposite pinnae, the pinnae with 1–several linear or linear-oblong acute lobes to deeply pinnatifid or pinnate with up to 16 lobes or pinnules, glabrous above, closely appressed pubescent beneath.
Inflorescence with main axis up to 24 cm long, usually with several simple lateral branches from near the base, appressed-pubescent towards the base but glabrous distally; pedicels 9–15 mm long, glabrous.
Perianth 7–10 mm long, glabrous, bright yellow to orange or reddish.
Fruits c. 15 × 10 mm, blackish, glabrous.
Tree up to 30 m high.
Life form perennial
Growth form tree
Growth support free-standing
Foliage retention evergreen
Sexuality hermaphrodite
Pollination entomogamy
Spread -
Mature width (meter) 4.0 - 9.0
Mature height (meter) 25.0 - 30.0
Root system -
Rooting depth (meter) 0.9
Root diameter (meter) -
Flower color
Blooming months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Fruit color
Fruiting months
JanFebMar
AprMayJun
JulAugSep
OctNovDec
Nitrogen fixer -
Photosynthetic pathway c3

Environment

Already long ago introduced in Malaysia and used as a roadside tree. It was formerly also used rather extensively as a shade-tree in tea-and coffee-plantations, but this practice has been abandoned as it is assumed that the roots and stumps left after felling disperse dangerous root fungi. It shows a rapid growth and some resistance against wind which capacities are used by the Forestry Service for reafforestation on bad, bare or eroded soils in the montane zone, either in pure or mixed stands. Results in Bali were rather promising ( de Voogd Tectona 28 1935 461 ). The species shows a great adaptability to various climates; Coster ( Coster Tectona 30 1937 16 ) says that whereas it stands severe droughts in Australia it grows also under tropical everwet conditions; at Bogor it was classified as a plant with a rather strong evaporation. On the whole it does best under seasonal conditions at average altitude, preferably 500-1600 m, though cultivation is possible from low altitude to c. 2000 m; reported to be frost-resistant on Mt Tengger at 2000 m
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A subtropical plant. It can grow in temperate and tropical places. It is native to E Australia. It is moderately frost hardy. It can grow in fairly dry conditions. It needs well drained soil. It can grow in full sun or light shade. In China it is cultivated as an ornamental along roadsides at low altitudes. In India it is used as a shade in coffee at elevations of 1200-2300 m altitude. It cannot tolerate lime and does best in acid soils. Once fully established in can tolerate temperatures down to 10°C. It suits hardiness zones 8-12.
Grows usually in basaltic soils in three distinct habitats: riverine gallery rainforest and rainforest margins; riverine sclerophyll communities with Allocasuarina cunninghamiana ; and Araucaria forest and vine thickets on higher slopes.
Riverine rain forests, usually by water, on soils of fairly high fertility. Also found in vine forests, which cover extensive areas including steep upper-valley slopes.
Riverine rain forests, usually by water, on soils of fairly high fertility. Also found in vine forests, which cover extensive areas including steep upper-valley slopes.
Light 6-8
Soil humidity 3-6
Soil texture 1-6
Soil acidity 3-6
Soil nutriment -
Hardiness (USDA) 9-11

Usage

Uses. Wood with prominent rays, of a light pinkish colour to reddish-brown, light, elastic, durable, easy to work, used for tea-boxes and cabinet-work, excellent for staves of casks, not resistant to termites.
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The nectar of the flowers are used to make sweet drinks. The nectar can be sucked directly from the flowers. Caution: It can cause skin rashes and the plants can contain cyanide.
Uses animal food bee plant charcoal dye environmental use fiber food fuel gene source gum invertebrate food material medicinal ornamental poison tea timber vertebrate poison wood
Edible flowers leaves nectars
Therapeutic use Central nervous system depressants (aerial part), Diuretics (aerial part), Spasm (aerial part), Antioxidants (leaf), Central nervous system diseases (unspecified), Diuretics (unspecified), Parasympatholytics (unspecified)
Human toxicity -
Animal toxicity -

Cultivation

Plants can be grown from fresh seed. They can also be grown from cuttings and grafting.
Mode cuttings seedlings
Germination duration (days) 20 - 25
Germination temperacture (C°) 23 - 26
Germination luminosity light
Germination treatment soaking
Minimum temperature (C°) -7
Optimum temperature (C°) 15 - 28
Size -
Vigor -
Productivity -

Images

Habit

Grevillea robusta habit picture by ian connop (cc-by-sa)
Grevillea robusta habit picture by Lisa Ani (cc-by-sa)

Leaf

Grevillea robusta leaf picture by Pazzelli (cc-by-sa)
Grevillea robusta leaf picture by Claudio Malpede (cc-by-sa)
Grevillea robusta leaf picture by Sepúlveda Alejandro (cc-by-sa)

Flower

Grevillea robusta flower picture by Remo Cela (cc-by-sa)
Grevillea robusta flower picture by Kailash Varma (cc-by-sa)
Grevillea robusta flower picture by jm jacques (cc-by-sa)

Fruit

Grevillea robusta fruit picture by Giorgio Contarini (cc-by-sa)
Grevillea robusta fruit picture by Daniel Grixti-Cheng (cc-by-sa)

Distribution

Grevillea robusta world distribution map, present in Argentina, Australia, Bangladesh, Bolivia (Plurinational State of), Brazil, Central African Republic, China, Cameroon, Cook Islands, Colombia, Costa Rica, Dominican Republic, Ecuador, Spain, Guinea, Guadeloupe, Guam, Honduras, Haiti, India, Jamaica, Libya, Sri Lanka, Morocco, Madagascar, Mexico, Marshall Islands, Myanmar, Mozambique, Montserrat, Mauritius, Nicaragua, Niue, Nepal, New Zealand, Pakistan, Philippines, Puerto Rico, Réunion, Sao Tome and Principe, Trinidad and Tobago, Taiwan, Province of China, United States of America, Venezuela (Bolivarian Republic of), Viet Nam, and South Africa

Conservation status

Grevillea robusta threat status: Least Concern

Identifiers

LSID urn:lsid:ipni.org:names:50798-3
WFO ID wfo-0000709544
COL ID 3HCXT
BDTFX ID 53331
INPN ID 100580
Wikipedia (EN) Link
Wikipedia (FR) Link

Synonyms

Stylurus robustus Grevillea umbratica Grevillea venusta Grevillea robusta var. forsteri Grevillea robusta