The Anacardiaceae, commonly known as the cashew family[1] or sumac family, are a family of flowering plants, including about 83 genera with about 860 known species.[2] Members of the Anacardiaceae bear fruits that are drupes and in some cases produce urushiol, an irritant. The Anacardiaceae include numerous genera, several of which are economically important, notably cashew (in the type genus Anacardium), mango, Chinese lacquer tree, yellow mombin, Peruvian pepper, poison ivy, poison oak, sumac, smoke tree, marula and cuachalalate. The genus Pistacia (which includes the pistachio and mastic tree) is now included, but was previously placed in its own family, the Pistaciaceae.[3]
Trees or shrubs, each has inconspicuous flowers and resinous or milky sap that may be highly poisonous, as in black poisonwood and sometimes foul-smelling.[4]Resin canals located in the inner fibrous bark of the fibrovascular system found in the plant's stems, roots, and leaves are characteristic of all members of this family; resin canals located in the pith are characteristic of many of the cashew family species and several species have them located in the primary cortex or the regular bark. Tannin sacs are also widespread among the family.[5]
The wood of the Anacardiaceae has the frequent occurrence of simple small holes in the vessels, occasionally in some species side by side with scalariform holes (in Campnosperma, Micronychia, and Heeria argentea (Anaphrenium argenteum). The simple pits are located along the vessel wall and in contact with the parenchyma.[5]
Leaves are deciduous or evergreen, usually alternate (rarely opposite),[6] estipulate (without stipule) and imparipinnate (rarely paripinnate or bipinnate), usually with opposite leaflets (rarely alternate), while others are trifoliolate or simple or unifoliolate (very rarely simple leaves are palmate). Leaf architecture is very diverse. Primary venation is pinnate (rarely palmate). Secondary venation is eucamptodromous, brochidodromous, craspedodromous or cladodromous (rarely reticulodromous) Cladodromous venation, if present is considered diagnostic for Anacardiaceae.[4][7]
Flowers grow at the end of a branch or stem or at an angle from where the leaf joins the stem and have bracts.[4]Often with this family, bisexual and male flowers occur on some plants, and bisexual and female flowers are on others, or flowers have both stamens and pistils (perfect). A calyx with three to seven cleft sepals and the same number of petals, occasionally no petals, overlap each other in the bud. Stamens are twice as many or equal to the number of petals, inserted at the base of the[6] fleshy ring or cup-shaped disk, and inserted below the pistil(s).[4]Stamen stalks are separate, and anthers are able to move.[6]Flowers have the ovary free, but the petals and stamen are borne on the calyx.[4]In the stamenate flowers, ovaries are single-celled. In the pistillate flowers, ovaries are single or sometimes quadri- or quinticelled. One to three styles and one ovule occur in each cavity.[6]
Seed coats are very thin or are crust-like. Little or no endosperm is present. Cotyledons are fleshy.[6]Seeds are solitary with no albumen around the embryo.[4]