Resiniferous Plant

a plant that contains resin in various organs. The resins are normal metabolic products that accumulate in the resin ducts of the trunk, roots, leaves, bark tumors, and other receptacles.

Resiniferous plants belong to 26 families, half of which occur in the tropics. The resins of tropical plants vary greatly in chemical composition. Of the family Araucariaceae, species of the genus Dammar yield the resin dammar, and species of the genera Araucaria and Vateria yield copal. The sandarac tree and plants of the genus Tetraclinis of the family Cypressaceae yield sandarac. Acaroid resin is obtained from the grass tree (Xanthorrhoea) of the family Liliaceae, copal is produced by Hymenaea and Trachylobium of the family Caesalpiniaceae, and copaiba balsam is produced by Copaifera. Acacias and albizzias (with the help of insects) of the family Mimosaceae yield lac, and the Japanese varnish tree and the mastic tree of the family Anacardiaceae yield gum mastic.

Of importance in countries having a temperate climate are resiniferous plants of the family Pinaceae. Various pine, spruce, and larch species yield oleoresin from which rosin and turpentine are obtained. Some firs also yield balsam. Of the family Umbelliferae, Dorema yields ammonia resin, and Ferula yields galbanum, asafetida, and other resins. Several spurge species of the family Euphorbiaceae contain resins in the milk vessels.

Resins and balsams are sometimes produced by plant cells in response to injury. Their biological function is apparently related to protecting the plants from being eaten by animals and from infestation by parasitic fungi.