"Although
tea tree oil is normally extracted
from
Melaleuca alternifolia
commercially, it can also
be extracted from
Melaleuca dissitiflora
and
Melaleuca linariifolia.
Tea tree oil is defined by
international standard
ISO 4730 ("Oil of
Melaleuca, Terpinen-4-ol
type"), which specifies levels
of 14 components which are
needed to define the oil as
"tea tree oil." see (http://en.wikipedia.org/wiki/Tea_tree_oil)