1. Family: Proteaceae Juss.
    1. Genus: Grevillea R.Br. ex Knight
      1. Grevillea robusta A.Cunn. ex R.Br.

        Grevillea robusta was first described in 1830 by Allan Cunningham, who was employed by the Superintendent of Kew, William T. Aiton, to write Hortus Kewensis and was then sent by Kew to collect plants in Brazil, Australia and New Zealand. Allan succeeded his brother Richard as Superintendent of the Botanic Garden in Sydney in 1836. In subtropical areas, silky oak forms a large upright tree with spreading lower branches. Its flowers, which open from October to December, are rich in nectar and attract birds and fruit bats. The seedlings, with their ferny foliage and silky new growth, make attractive houseplants.

    [FTEA]

    Proteaceae, R.K. Brummitt & Serena K. Marner. Flora of Tropical East Africa. 1993

    Habit
    Tree up to 30 m. high.
    Leaves
    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.
    Inflorescences
    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
    Perianth 7-10 mm., glabrous, bright yellow to orange or reddish.
    Fruits
    Fruits ±15 ×10 mm., blackish, glabrous.
    [KSP]

    Kew Species Profiles

    General Description
    Silky oak is one of the finest flowering trees from Australia, with fern-like leaves and rich yellow, comb-like flowers in late spring.

    Grevillea robusta was first described in 1830 by Allan Cunningham, who was employed by the Superintendent of Kew, William T. Aiton, to write Hortus Kewensis and was then sent by Kew to collect plants in Brazil, Australia and New Zealand. Allan succeeded his brother Richard as Superintendent of the Botanic Garden in Sydney in 1836. In subtropical areas, silky oak forms a large upright tree with spreading lower branches. Its flowers, which open from October to December, are rich in nectar and attract birds and fruit bats. The seedlings, with their ferny foliage and silky new growth, make attractive houseplants.

    Species Profile

    Geography and distribution

    Native to Australia, silky oak is found in the rainforests of south-eastern Queensland and north-eastern New South Wales. It has been planted throughout the tropics and subtropics as a shade tree and in agroforestry, and has become naturalised in many countries. In some places, such as Hawaii, parts of Australia, Mauritius, and Brazil, it has become invasive, out-competing native vegetation.

    Description

    Silky oak is a tall, upright tree measuring up to 30 m tall (although most commonly reaching around 10 m). Its bark is greyish and deeply grooved. Its leaves are much divided, and are dark green above, silky and silvery beneath, measuring 15-30 cm long. The leaves are rather leathery in texture. The flowers are bright orange-yellow, and are held horizontally in crowded racemes 10-15 cm long, each with a conspicuous, upright, cone-shaped pollen-presenter. The fruits are flattened, 15-20 mm long, with a persistent style and one or two brown seeds, each with a narrow wing surrounding it.

    Uses

    Grevillea robustais commonly planted as a shade tree or street tree in tropical and subtropical areas. Its timber is used for making furniture, and in Sri Lanka and East Africa the tree is planted as a fuelwood species.

    It is fast-growing, drought-resistant and tolerant of poor soil, so has been used for reclamation of deforested land in Africa and America. However, its leaves produce allelopathic compounds which inhibit the establishment of other plants (including native species), and in some places, such as Hawaii, silky oak is invasive and considered a serious weed.

    In China, South India and Sri Lanka it has often been planted to provide shade in tea plantations, and in Brazil, India and Hawaii for shade in coffee plantations.

    Young plants are grown for their foliage, and make attractive indoor plants, or greenhouse plants in temperate climates. In warmer climates the resulting trees are too large for most urban gardens. The flowers, which are produced in large quantities following a dry winter and spring, are rich in nectar and attract birds and insects, as well as fruit bats. The cut leaves are used in floristry.

    Millennium Seed Bank: Seed storage

    Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those likely to be of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

    Description of seeds:Average 1,000 seed weight = 20 gNumber of seed collections stored in the Millennium Seed Bank:OneSeed storage behaviour:Orthodox (the seeds of this plant survive drying without significant reduction in their viability, and are therefore amenable to long-term frozen storage such as at the MSB)

    Cultivation

    Silky oak is easy to grow in subtropical areas, surviving even in poor and degraded soils. In cold areas it is easily grown as a seedling, in a large pot of sandy soil, with the stem trained up a slender cane. In winter, the plant should be given as much light as possible, and kept rather dry. The leaves would probably survive a few degrees of overnight frost. Propagation is best by seed.

    This species at Kew

    Samples of wood, bark and gum from Grevillea robusta are held in the behind-the-scenes Economic Botany Collection at Kew, where they are made available to researchers by appointment.

    Distribution
    Australia
    Ecology
    Rainforest.
    Conservation
    Not threatened.
    Hazards

    The leaves are poisonous and can cause skin irritation. Cases of severe dermatitis are rare, but have been reported.

    [FZ]

    Proteaceae, S.M. Chisumpa†, R.K. Brummitt and S. Marner. Flora Zambesiaca 9:3. 2006

    Habit
    Tree up to 30 m high.
    Leaves
    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.
    Inflorescences
    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
    Perianth 7–10 mm long, glabrous, bright yellow to orange or reddish.
    Fruits
    Fruits c. 15 × 10 mm, blackish, glabrous.
    [KSP]
    Use
    Ornamental, shade tree, timber for furniture.

    Images

    Distribution

    Found In:

    Cameroon, New South Wales, Queensland

    Introduced Into:

    Argentina Northeast, Assam, Bangladesh, Canary Is., Cape Verde, Costa Rica, Cuba, Easter Is., El Salvador, Eritrea, Ethiopia, Gambia, Gulf of Guinea Is., Italy, Kenya, Mauritius, Mexico Southwest, Mozambique, New Zealand North, Norfolk Is., Rwanda, Réunion, Society Is., Solomon Is., St.Helena, Trinidad-Tobago, Venezuela, Venezuelan Antilles, Zambia, Zaïre

    Common Names

    English
    Silky oak

    Grevillea robusta A.Cunn. ex R.Br. appears in other Kew resources:

    Date Identified Reference Herbarium Specimen Type Status
    Jan 1, 1979 Cunningham, A. [s.n.], Queensland K000799417 Unknown type material
    Jan 1, 1979 Cunningham, A. [72], Queensland K000799418 Unknown type material
    Jan 1, 1979 Cunningham, A. [11], Queensland K000799419 syntype

    First published in Suppl. Prodr. Fl. Nov. Holl.: 24 (1830)

    Accepted in:

    • [2] (2014) Manual de Plantas de Costa Rica 7: 1-840. Missouri Botanical Garden Press.
    • [5] Mostaph, M.K. & Uddin, S.B. (2013) Dictionary of plant names of Bangladesh , Vasc. Pl.: 1-434. Janokalyan Prokashani, Chittagong, Bangladesh.
    • [7] (2012) Englera 29-2: 1-300
    • [10] (2011) Bothalia, A Journal of Botanical Research 41: 41-82
    • [11] Onana, J.M. (2011) The vascular plants of Cameroon a taxonomic checklist with IUCN assessments . National herbarium of Cameroon, Yaoundé.
    • [12] (2010) Journal of East African Natural History 99: 129-226
    • [13] (2009) Pleione 3: 190-200
    • [14] Hokche, O., Berry, P.E. & Huber, O. (eds.) (2008) Nuevo Catálogo de la Flora Vascular de Venezuela . Fundación Instituto Botánico de Venezuela.
    • [17] Govaerts, R. (2003) World Checklist of Seed Plants Database in ACCESS G: 1-40325
    • [19] (1994) Flora of Australia 49: 1-681. Australian Government Publishing Service, Canberra.
    • [21] (1993) Sommerfeltia 17: 1-295
    • [22] (1991) Palmarum Hortus Francofurtensis 3: 1-108
    • [23] Jones, M. (1991) A checklist of Gambian plants . Michael Jones, The Gambia College.
    • [28] (1973) Bulletin of the British Museum (Natural History). Botany 4: 325-411
    • [29] (1948-1963) Flore du Congo Belge et du Ruanda-Urundi 1-10:

    Literature

    • [1] (2016) Phytotaxa 250: 1-431
    • [3] (2014) Manual de Plantas de Costa Rica 7: 1-840. Missouri Botanical Garden Press.
    • [4] (2013) Index synonymique de la flore d'Afrique du nord 5: 1-451. Éditions des conservatoire et jardin botaniques, Genève.
    • [6] Mostaph, M.K. & Uddin, S.B. (2013) Dictionary of plant names of Bangladesh , Vasc. Pl.: 1-434. Janokalyan Prokashani, Chittagong, Bangladesh.
    • [8] Garcia-Mendoza, A.J. & Meave, J.A. (eds.) (2012) Diversidad florística de Oaxaca: de musgos a angiospermas (colecciones y listas de especies) , ed. 2: 1-351. Instituto de Biología, Universidad Nacional Autónoma de México.
    • [9] Lambdon, P. (2012) Flowering plants & ferns of St Helena . Pisces publications for St Helena nature conservation group.
    • [15] Hokche, O., Berry, P.E. & Huber, O. (eds.) (2008) Nuevo Catálogo de la Flora Vascular de Venezuela . Fundación Instituto Botánico de Venezuela.
    • [16] (2006) Flora Zambesiaca 9(3): 1-277. Royal Botanic Gardens, Kew.
    • [18] (2000) Flora of Ethiopia and Eritrea 2(1): 1-532. The National Herbarium, Addis Ababa University, Ethiopia & The Department of Systematic Botany, Upps.
    • [20] (1994) Flora of Australia 49: 1-681. Australian Government Publishing Service, Canberra.
    • [24] Elliot, W.D. & Jones, D.L. (1990). Encyclopedia of Australian Plants Suitable for Cultivation, Volume 5. Lothian, Melbourne, Sydney, Auckland.
    • [25] (1988) Research Bulletin Dodo Creek Research Station 7: 1-203
    • [26] (1982) Flore des Mascareignes 153-160: 1. IRD Éditions, MSIRI, RBG-Kew, Paris.
    • [27] Desmond, R. (1977). Dictionary of British and Irish Horticulturists. Taylor and Francis Ltd, London.
    • [30] IUCN Invasive Species Specialist Group, Global Invasive Species Database.

    Sources

    Flora of Tropical East Africa
    [A] http://creativecommons.org/licenses/by-nc-sa/3.0

    Flora Zambesiaca
    [B] http://creativecommons.org/licenses/by-nc-sa/3.0

    International Plant Names Index
    The International Plant Names Index (2016). Published on the Internet http://www.ipni.org
    [C] © Copyright 2016 International Plant Names Index. https://creativecommons.org/licenses/by/3.0

    Kew Species Profiles
    Kew Species Profiles
    [D] http://creativecommons.org/licenses/by-nc-sa/3.0
    [E]

    World Checklist of Selected Plant Families
    World Checklist of Selected Plant Families(2016). Published on the Internet http://apps.kew.org/wcsp/
    [F] See http://kew.org/about-kew/website-information/legal-notices/index.htm You may use data on these Terms and Conditions and on further condition that: The data is not used for commercial purposes; You may copy and retain data solely for scholarly, educational or research purposes; You may not publish our data, except for small extracts provided for illustrative purposes and duly acknowledged; You acknowledge the source of the data by the words "With the permission of the Trustees of the Royal Botanic Gardens, Kew" in a position which is reasonably prominent in view of your use of the data; Any other use of data or any other content from this website may only be made with our prior written agreement. http://creativecommons.org/licenses/by-nc-sa/3.0
    [G] © Copyright 2016 International Plant Names Index and World Checkist of Selected Plant Families. https://creativecommons.org/licenses/by/3.0