MASTERWORT

Imperatoria ostruthium

(Formerly: Peucedanum ostruthium)
Carrot Family [Apiaceae]

month8jun month8june month8jul month8july

status
statusZarchaeophyte
flower
flower8white
flower
flower8pink
inner
inner8green
morph
morph8actino
petals
petalsZ5
type
typeZumbel
stem
stem8round
stem
stem8ribbed
stem
stem8hollow
sex
sexZbisexual
sex
sexZmale

21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
An erect plant which is hairless or nearly hairless and with long, wide, almost linear sheathing (which your Author calls 'armpits') beneath the junction of every branch off the main stem. These 'armpits' are paler in colour than the other green parts and terminate in a leaf with 3 leaflets, each leaflet being deeply cut into 3 or so 'leafletlets' (or lobes if you must).


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
Any upper leaves are small. The umbels are compound, with between 30 and 60 unequally-long rays, between 1 to 5cm long and with tiny half-round pimples on the upper sides. The stem leading up to each compound umbel is longer than the rays. There are no bracts (or rarely only 1 or 2) on the umbel, and on the umbellets above the umbel there are only a few, linear bracts (seen sticking upwards above both the lower flower clusters. The terminal umbel (usually the highest) has bisexual flowers; all the other umbels have only male flowers.


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
The pale sheaths terminate in a leaf with 3 leaflets, each leaflet being deeply cut into 3 or so lobes (some clipped off the frame). This particular sheath has 6 reddish-brown pointed teeth, one in each corner and two in the centre, maybe acting as structural stiffening components to keep the heavy leaflet at the end from drooping downwards.
A branch umbel at top left has male-only flowers. The bracteoles of the umbellets are linear and sticking up.


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
Whereas this sheath has either no teeth or less distinct teeth. It is wrinkled and seems to have a purplish object inside and on the main stem. The stems are hollow, round and with weak ribs.


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
The leaves have distinct veins and are irregularly doubly-toothed.


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
Each leaflet is deeply cut into several irregular lobes.


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson


21st June 2013, Teesdale, Co. Durham. Photo: © Dawn Nelson
Leaf teeth very irregular, some very long.


Not to be semantically confused with : Great Masterwort aka Pink Masterwort (Astrantia major) [a plant with similar name which belongs in the same Apiaceae family but which is an atypical umbellifer and looks nothing like Masterwort]

Uniquely identifiable characteristics

Distinguishing Feature :

Masterwort is native to the mountains of central and southern Europe; in the UK it is an archaeophyte which was once cultivated as both a pot-herb and for veterinary use. It is naturalised in scattered places mainly in the North of England in grassy places, riversides and marshy fields. It is used overseas as a flavouring in various liqueurs and bitters. The roots and leaves have also variously been used as an incense, or as a tincture or as a fumigant.

Masterwort contains several coumarins and furocoumarins, the first four being named after it: OxyPeucedanin, Ostruthol, Ostruthin and Osthole, plus Imperatorin, iso-Imperatorin. But since those secondary metabolites were named, Masterwort has had a botanical name change from Peucedanum ostruthium to Imperatoria ostruthium, thus those chemicals referring to Peucedanum (just OxyPeucedanin) are now misnomers.

FUROCOUMARINS and COUMARINS


First the 4 FuroCoumarins:

IsoImperatorin is the isomer of Imperatorin. The difference being that the side branch off the 3 fused rings of FuroCoumarin has simply swapped from being attached at the bottom of the central ring to the top of it.




OxyPeucedanin is similar to IsoImperatorin, but the 5 carbon atoms of the side-branch have shuffled around a bit at the top to form a 3-membered epoxy ring of Ethylene Oxide aka Oxirane (the triangle with the oxygen atom in the ring). This Oxirane will probably make OxyPeucedanin more toxic than any of the other molecules shown in this panel.

Ostruthol has many additional moieties in the side chain, but lacks the Oxirane moiety of OxyPeucedanin.




The above two are just Coumarins, albeit with side branches.

Osthol is more similar to Imperatorin but with a shorter side chain without the oxygen atom. All that is left of the Furo part is an -O- side branch on the bottom left.

Ostruthin is a hydroxy Coumarin with a Geranyl side chain.


  Imperatoria ostruthium  ⇐ Global Aspect ⇒ Apiaceae  

Distribution
 family8Carrot family8Apiaceae
 BSBI maps
genus8Imperatoria
Imperatoria
(Masterwort)

MASTERWORT

Imperatoria ostruthium

(Formerly: Peucedanum ostruthium)
Carrot Family [Apiaceae]