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Conservation Status
IUCN: not evaluated
USFWS: None
Kamaui Aiona, Director of the Kahanu Garden of the NTBG speaking about Macadamia integrifolia
Family: PROTEACEAE Genus: Macadamia Species: integrifolia Species Author: Maiden & Betche Vernacular: Macadamia nut, Queensland nut
Macadamias are large, spreading evergreen trees reaching 30 to 40 ft. high and almost as wide. More upright types are known and being selected because of their suitability for closer planting. The bark is rough, brown and dark red when cut. The Macadamia has proteoid roots, dense clusters of short lateral rootlets in well defined rows around the parent root axis. The prime function of such roots appears to be in increasing the surface area of the root system for maximum absorption. The vigor of seedlings appears to be related to the degree of proteoid root development. The leaves of Macadamia integrifolia are 8 to 11 inches in length and occur usually in whorls of 3. The adult leaves are entire with few spines. New growth is pale green. Flowers are borne on long narrow racemes arising from the axils of leaves or the scars of fallen leaves. They may be borne on the new growth if it is mature, but more often on the two, or three season's growth preceding the most recently matured flushes. The flowers, about 1/2 inch long, are perfect but incomplete in that they have no petals, but four petaloid sepals. Macadamia integrifolia has creamy white flowers borne in clusters 6 to 12 inches long. Macadamia nuts have a very hard seed coat enclosed in a green husk that splits open as the nut matures. As the common name indicates, this seed coat is smooth in the case of Macadamia integrifolia. It holds a creamy white kernel containing up to 80% oil and 4% sugar. When roasted it develops a uniform color and texture.
(University of California. 2004.)
Macadamia integrifolia can also be used as a timber tree and ornamental species.
(Information for this species compiled and recorded by Camelia Cirnaru, NTBG Consultant.)
Macadamia integrifolia is native to southeastern Queensland where it grows in the rain forests and close to streams.
(University of California. 2004.)
Macadamias are considered to be among the finest table nuts in the world. They contain high quantities of oil, and are therefore very fattening.
Macadamia nuts are eaten raw or roasted and salted. The nuts are also used to make an edible bland salad oil. Years ago a coffee-like beverage known as "almond coffee" was marketed from the seeds.
(University of California. 2004.)
Macadamias can self pollinate, although varieties vary from being totally self-compatible to being almost self-sterile. Wind pollination may play some role, but bees are apparently the major agent in pollination.
Cross-pollination by hand has been shown to increase nut set and quality.
(University of California. 2004.)
The Macadamia was introduced into Hawaii about 1881 where it was used as an ornamental tree and for reforestation purposes. The Hawaii Agricultural Experiment Station named and introduced several promising selections in 1948, which led to the modern Macadamia industry in Hawaii. In California two seedling Macadamias were planted in the early 1880's and are still standing on the Berkeley campus of the University of California. The importation of improved and named varieties into California from Hawaii began about 1950.
Macadamias are also commercially important in Australia, South Africa and Central America.
(University of California. 2004.)
We currently have 13 herbarium specimens for Macadamia integrifolia in our collection. Click on any specimen below to view the herbarium sheet data.
