The alkaloid[35] furnishing families belong, with few exceptions, to
the dicotyledons. The colchiceae, from which is obtained veratrine,
form an exception among the monocotyledons. The alkaloids of the
fungus have already been noted.
[36]Among the greater number of plant families, no alkaloids have been
found. In the labiatae none has been discovered, nor in the compositae
among the highest plants.
One alkaloid is found in many genera of the loganiaceae; berberine in
genera of the berberidaceae, ranunculaceae, menispermaceae, rutaceae,
papaveraceae, anonaceae.
Waxes are widely distributed in plants. They occur in quantities in
some closely related families.
Ethereal oils occur in many families, in the bark, root, wood, leaf,
flower, and fruit; particularly in myrtaceae, laurineae, cyperaceae,
crucifereae, aurantiaceae, labiatae, and umbelliferae.
Resins are found in most of the higher plants. Tropical plants are
richer in resins than those of cold climates.
Chemical resemblance between groups, as indicating morphological
relations, has been well shown. For example: the similarity[37] of the
viscid juices, and a like taste and smell, among cactaceae and
portulaceae, indicate a closer relationship between these two orders
than botanical classification would perhaps allow.
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