Uniquely identifiable characteristics: there is no other plant quite like this.
Distinguishing Feature : the long protruding purple-brown stamens sticking out from pale creamy longish flowers. Leaves deeply net-grooved like miniature grykes. Smells nice when crushed.
Wood Sage both smells and tastes similar to Hops (amongst many other oils it contains one of the ingredients of hops, namely humulene epoxide) and is thus sometimes used to give beer a bitter taste as well as to clarify the beer (make the yeast sink). Thus used, it endows the beer with a rich hue.
The text books say Wood Sage prefers acid soils but many of the above examples are growing on limestone areas. Also grows on dunes, screes and dry heath. It is a woody undershrub. The flowers are pale yellowish creamy green, the stem square (with perhaps some round sections) and very hairy (with short downwardly-directed hairs), the leaves are light green and very deeply-net-veined, hairy underneath.
Wood Sage contains the mono-cyclic sesquiterpene, Humulene Epoxide, a derivative of Humulene, which also has an 11-membered carbon ring. Humulene is one of the aromatic components of Hops which contributes to the flavour of beer. Humulene occurs not only in Hops (Humulus lupus) but also in the only other relative of Hops - Hemp (Cannabis sativa).
In Spain it has also been found to contain Germacrene B (at 25%),
α-Humulene (8%), α-Cubebene (8%) and Germacrene D (6%).
Wood Sage is commonly used in alcoholic beverages such as Vermouth and tonics, for it has an extremely bitter taste, due mostly to the compound Teucrin A which it contains. The maximum permissible amount of Teucrin A in any drink has now been increased from 2 to 5mg/kg at the bequest of the Italian Government, whose local drinks would have otherwise fallen foul of recent European Legislation on the maximum permissible amount.
Like Teucrine above, Teucrine A is another toxic furano neoclerodene diterpenoid which is contained not only in Wood Sage but also other flowers belonging to the Teucrium Genus, such as
Germander and Feverfew. It is hepatotoxic, damaging the liver.
Notice the similarity to Humulene above; apart from the two extra spiro furano rings, just an extra carbon atom is at the centre of the large ring of humulene.
Other similar diterpenoids found within Teucrium species are
Teucrolivin A, and
Plants of Genus Teucrium, which includes Wood Sage and Wall Germander, contain the hepatotoxic furano neo-clerodane diterpenoids (although Teucrine itself is not a furano compound).