Resins = lipid-soluble mixtures of volatile and non-volatile terpenoid
and phenolic secondary compounds.
Gums and Mucilages = water soluble but high molecular weight
polysaccharides. The two classes of compounds are similar but gums are
only found in cavities (e.g., Acacia, Prosopis, Eucalyptus,
whereas mucilages are found in a diversity of structures including
trichomes, canals, and secretory cells.
Latex = lipid-soluble often milky white emulsions with a diversity of
substances in solution or in suspension that can include terpenoids,
phenolic compounds, proteins, alkaloids, minerals, and carbohydrates.
Latex is found in specialized tubes called laticifers that often ramify
through the pith, foliar mesophyll, and especially in vascular tissues
including phloem and xylem rays. In some species the laticifers form a
network just external to the phloem with branches into the cortex (Langenheim,
Langenheim JH (2003) Plant Resins: Chemistry, Evolution,
Ecology and Ethnobotany. Timber Press, Portland, Oregon, 586 pages
photograph at the top of the page shows white latex oozing out of a
rubber tree. This latex is the raw material used to produce