There exists in the flora of the United States a large number of plant
families which include species of highly odorous character, many of
which are known and described botanically as possessing peculiar
aromas, but which have received no attention from the standpoint of
their volatile-oil content. The various sections of the country, with
their marked differences of soil and climate, possess floras peculiar
to themselves which, if investigated, would doubtless reveal many
plants valuable for their volatile oils. For example, in Florida and
the South Atlantic States are found many plants with agreeable odors
which thrive only in the climate and soil of that region. The Central
Western States produce numerous species of sages and other plants found
only in arid and semiarid climates. In the extreme Western States are
numerous wild aromatic plants, some of which have been distilled and
analyses made of the oils obtained therefrom.
PRESENT PRODUCTION OF VOLATILE OILS FROM WILD PLANTS NATIVE TO THE
UNITED STATES.
Only a very few of the wild plants native to this country have been
distilled and their volatile oils used for commercial purposes. Among
these may be mentioned longleaf pine, sassafras, wintergreen, sweet
birch, pennyroyal, horsemint, and Canada fleabane.
The first and by far the most important oil distilled from a wild plant
indigenous to the United States was turpentine oil, which was distilled
as early as the middle of the eighteenth century. The production of
this oil is rapidly declining, owing principally to the employment of
very wasteful methods, which have resulted in the destruction of many
of the large pine forests. Turpentine is still obtained, however, from
the longleaf pine (_Pinus palustris_), which occurs quite abundantly
in the South Atlantic States from Virginia to Florida. The price of
this valuable oil has risen so rapidly in recent years, owing to the
shortage of raw material from which it is distilled, that a suitable
substitute would be most desirable. This problem is now receiving
the attention of scientific research workers, but no satisfactory
substitute which can supply the trade has yet been found.
The commercial distillation of sassafras, wintergreen, and sweet birch
possibly rank next in importance, although the oils are produced on
a considerably smaller scale. These oils are used extensively by
perfumers, confectioners, and manufacturers of toilet soaps. The plants
are gathered in their native habitats and the quality of the oil
depends upon the freedom from extraneous material, which can be insured
only by extreme care in collection.
The production of pennyroyal and Canada fleabane oils from the wild
plants is also carried on in a small way. The oils from these plants
possess valuable therapeutic action and are used principally in
medicinal preparations.
Horsemint and wild bergamot are wild aromatic plants which have been
more recently distilled for their volatile oils. The use of these
plants was brought about by the discovery that their oils contain,
respectively, the valuable antiseptics thymol and carvacrol. The
production of the oils, however, is not being carried on to any great
extent.
These few species are practically the only wild aromatic plants of the
United States which are at present being utilized for their volatile
oils, and no attempt has yet been made to cultivate them in order to
improve the quality or to increase the yield of the oils.