Rue or Citrus Family

Evergreen or deciduous trees, shrubs or occasionally herbs with prickles or spines in some genera, usually hermaphrodite, rarely monoecious or dioecious. Leaves alternate or opposite, simple or compound, aromatic when crushed; stipules mostly absent, rarely gland-like. Flower clusters terminal or axillary, occasionally flowers solitary. Flowers regular or rarely irregular, mostly bisexual. Sepals (3–)4 or 5, free or united at the base. Petals (3–) 4 or 5, mostly free, united in Correa. Stamens same number or twice that of the petals, usually 8–10(– numerous), filaments free or cohering into bundles, glabrous or pubescent, anthers 2-locular, often apiculate, dehiscence introrse or lateral by longitudinal slits; nectar disc usually present. Ovary superior. Carpels (3–) 4 or 5, fused. Fruit a berry, drupe, capsule, follicle, cluster of samaras or a schizocarp of 3–4 roundish segments. Seeds usually solitary in each locule, rarely 2 (Cneorum)

Now includes Cneoraceae. This treatment follows Stevens, P.F. (2018, Angiosperm Phylogeny Website).

Rarely cultivated plants include the following: Acradenia frankliniae Kippist, a rainforest shrub or small tree from Tasmania with leaves of 3 leaflets that is occasionally cultivated in cooler districts; Acronychia oblongifolia (Hook.) Heynh., Common Acronychia, from Queensland, New South Wales and Victoria, a warm rainforest tree with solitary elliptic-obovate leaflets 4-12 cm long; Casimiroa edulis Llave, White Sapote, which has creamy edible sweet pulp and is sometimes grown in warm districts; Chorilaena quercifolia Endl., Chorilaena, from WA, a medium-sized shrub with characteristic oaklike lobed leaves and pendulous yellow-green flowers; Dictamnus albus L., Burning Bush, from Eurasia which exudes a volatile, flammable oil from the leaves; Melicope elleryana (F. Muell.) T. Hartley, Pink-flowered Evodia, a rainforest tree with trifoliate leaves, pink flowers and shiny black seeds [Euodia elleryana F.Muell.]; Flindersia australis R. Br., Crow's Ash (Teak), from Queensland and New South Wales, a rainforest tree occasionally seen in warm-climate gardens and as a street tree, with pinnate leaves, smooth grey bark and prickly fruit capsules 5-10 cm long; while F. maculosa (Lindl.) Benth, Leopardwood, is noted for its mottled white, cream and orange flaky bark; Geijera parviflora Lindl.,Wilga, from South Australia, Queensland and New South Wales, a tree with attractive pendulous branches and leaves but mostly found only in botanic gardens and a few parks such as 'Buda' in Castlemaine, Vic, and the Australian Border at the Royal Botanic Gardens Victoria (Melbourne Gardens); Phellodendron amurense Rupr. Cork Tree, from China and Japan, which grows to over 10 m tall and has long, pointed leaves that are waxy-blue below; Philotheca salsolifolia (Sm.) Druce from Queensland and New South Wales with linear glandular leaves and pink to purplish flowers about 2 cm wide; and Poncirus trifoliata (L.) Raf., Trifoliate Orange (Hardy Orange), from N China and Korea, a spiny deciduous tree sometimes used for hedging with leaves of 3 leaflets and flowers with 20-60 stamens.

An economically important family that is the source of edible citrus fruits and essential oils that are used in medicine and perfumery (bergamot); timber is obtained from several of the rainforest species. Cneorum tricoccon is used locally as a rouge, and the leaves and fruits as a purgative.

Leaves with a strong and characteristic sharp, often slightly foetid smell when crushed, the result of oils produced in small translucent black gland dots on the leaves, nectary disc usually present. Although the fruits are variable, many have a glandular-punctate pericarp (Stevens 2018).

About 161 genera and c. 2070 species from tropical to temperate regions, with centres of diversity in S Africa, S America and Australia. Australia has 41 genera and about 350 species.

Source: Spencer, R. (2002). Rutaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.

Updated by: Val Stajsic, April 2018

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kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Rosanae
order      Sapindales
Higher taxa
Subordinate taxa
genus        Adenandra Willd.
genus        Asterolasia F.Muell.
genus        Boronia Sm.
genus        Calodendrum Thunb.
genus        Choisya Kunth
genus        Citrus L.
genus        Cneorum L.
genus        Coleonema Bartl & Wendl.
genus        Correa Andrews
genus        Crowea Sm.
genus        Eriostemon Sm.
genus        Medicosma Hook.f.
genus        Murraya L.
genus        Nematolepis
genus        Phebalium Vent.
genus        Ruta L.
genus        Skimmia Thunb.
genus        Zieria Sm.