The prevalent bush plants are khansa (umbrella mimosa), acacias, aloes, and, especially, Boswellia and Commiphora, which yield highly fragrant resins and balsams, such as myrrh, frankincense (olibanum) and " balm of Gilead."
CINNAMIC ACID, or Phenylacrylic Acid, C9H80 2 or C 6 H 5 CH: CH COOH, an acid found in the form of its benzyl ester in Peru and Tolu balsams, in storax and in some gumbenzoins.
Resins when soft are known as oleo-resins, and when containing benzoic or cinnamic acid they are called balsams. Other resinous products are in their natural condition mixed with gum or mucilaginous substances and known as gum-resins.
For quick growing plants, however, as for example most annuals cultivated in pots, such as balsams, cockscombs, globe-amaranths and the like, for cucumbers, and for young soft-wooded plants generally, it is exceedingly useful, both by preventing the consolidation of the soil and as a manure.
It occurs naturally in some resins, especially in gum benzoin (from Styrax benzoin), in dragon's blood, and as a benzyl ester in Peru and Tolu balsams. It can be prepared by the oxidation of toluene, benzyl alcohol, benzaldehyde and cinnamic acid; by the oxidation of benzene with manganese dioxide and concentrated sulphuric acid in the cold (L.
The herbaceous vegetation does not differ greatly, generically, from that of the east, and many species of Primulaceae, Ranunculaceae, Cruciferae, Labiatae and Scrophulariaceae occur; balsams abound, also beautiful forms of Campanulaceae, Gentiana, Meconopsis, Saxifraga and many others.
The oils are usually contained in special cells, glands, cavities, or canals within the plants either as such or intermixed with resinous substances; in the latter case the mixtures form oleo-resins, balsams or resins according as the product is viscid, or solid and hard.
In this group may be included the oleo-resins, such as copaiba, cubebs and Canada balsam; the gum-resins, such as asafetida, myrrh, ammoniacum and galbanum; and the true balsams, such as benzoin, storax, balsam of Tolu and balsam of Peru.
The resins when taken internally have much the same action as essential oils, which are closely allied chemically, while the benzoic and cinnamic acids in the balsams modify their actions very slightly.