LESSER MEADOW-RUE

Thalictrum minus

Buttercup Family [Ranunculaceae]

month8jul month8july month8aug

status
statusZnative
flower
flower8yellow
inner
inner8purple inner8red
inner
inner8cream
petals
petalsZ4
stem
stem8angular
stem
stem8round
toxicity
toxicityZmedium

3rd June 2016, lake shores, Ullswater, Pooley Bridge. Photo: © RWD
Very variable in height, from 25cm to more than 1m, this specimen is on the tall side but not yet in flower (although there are signs at the very top - which is just in front of the tree bole on the right). In the same place as the Globeflower, whose yellow globular flowers can be espied behind. (A young sapling of a Sycamore tree with its large palmate leaves is also in the way).


3rd June 2016, lake shores, Ullswater, Pooley Bridge. Photo: © RWD
The lower leaves are spread out in a stiff horizontal plane. The leaves are highly sub-divided, here are tripinnate, but the leaves can be 3- or 4-pinnate. Individual leaflets are ternate (with 3 lobes). The jizz of the leaf is unique and can be instantly recognised as that of Lesser Meadow-rue.


3rd June 2016, lake shores, Ullswater, Pooley Bridge. Photo: © RWD
The whole leaf conforms within the outline of a triangle.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
With leaves a little like those of Maidenhair Fern but with flowers.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
An open cluster of flowers at the top.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
A mass of tri-lobed leaves sprout on stalks from the thin stem.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
The leaves are much like those of Common Meadow-Rue and have three lobes, glaucous green to a reddening green, and slightly asymmetric.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
The flowers consist mainly of a dozen or so long, drooping white stamens with long axial yellow anthers.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
There are four yellowish petals, often tinged purple as here. Fresh anthers look more like miniature bananas.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
Fresh anthers look more like miniature bananas.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
Stems are reddish and round but sometimes with angular facets on the more substantial stems lower down.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
Leaves are 3- to 4-pinnate and with three or more rounded lobes. Note trefoil nature of the leaves.


2nd July 2011, Hightown, Sefton Coast. Photo: © RWD
Obverse of leaflets are embossed with prominent veins, and are whiter.


Uniquely identifiable characteristics

Distinguishing Feature :

No relation to : Rue or Goat's-Rue (Galega officinalis) nor Meadowsweet (Filipendula ulmaria) nor to Meadow-Foam (Limnanthes douglasii) [plants with similar names but which belong in differing families]. Nor is it related to Wall-rue (Asplenium ruta-muraria) which is a fern.

Somewhat surprisingly, both Common Meadow-Rue and Lesser Meadow-rue are members of the Buttercup Family.

Leaves reminiscent of those of Maidenhair Fern the garden plant. The plant is very variable and stands between 25cm to a metre tall, often zig-zagging on its thin and wiry stems. It grows on shingle or gravelly coastal shores and on coastal dunes, limestone rocks, mountain ledges and grassland. It is a garden plant that is widely naturalised, found here on MOD firing range land backing onto houses.

All parts of the plant are toxic and contains several alkaloids - Thalicmine, Thalicminine, Thalmidine, Thalmine, Thalictrimine, Thalicarpine, Thaliflavidine Magnoflorine, Glaucine, Berberine and Agrimoniin, a tannin.

Many of the above secondary metabolites (but not all) are IsoQuinoline or BisBenzylIsoQuinoline or aporphine or quaternary ProtoBerberines alkaloids - similar, but not identical, to those found in Common Meadow-Rue or many Poppies.

BENZYLISOQUINOLINE and BIS-BENZYLISOQUINOLINE ALKALOIDS

All parts of the plant are toxic and contain several toxic alkaloids - Thalicmine, Thalicminine, Thalmidine, Thalmine, Thalictrimine, Thalicarpine, Thaliflavidine (some of which which your Author cannot find on the internet, namely the latter), Magnoflorine, Glaucine, Berberine and Agrimoniin, a tannin (which is not an alkaloid).

Many of the above secondary metabolites (but not all) are BenzylIsoQuinoline or BisBenzylIsoQuinoline or Aporphines - being similar, but not identical, to those found in Common Meadow-Rue or in some Poppies.


Both Thalicmine and Thalicminine are Aporphine alkaloids.



Thalocarpine is the merger of an aporphine alkaloid (topmost moiety) with another aporphine moiety (albeit, one that has a broken central ring and is drawn the other way up).



Bisbenzylisoquinolines are two (hence the 'bis') conjoined Aporphines (aka BenzylIsoQuionoles). They can be conjoined in numerous contorted ways which gives them more of a 3-D (non-planar) structure and thus more likely to interact (adversely) with biologically important molecules within mammals (or other forms of life) with normally dire consequences for the recipient. Thalmine and Thalmidine are two such examples found in Lesser Meadow-Rue. There are others, but your Author could not find chemical structural formulae for them; mostly because they seam to have chemical synonyms, and it is those beginning with 'thal' which are the much less well known synonyms - but your Author lacks a name-comparison table, so is unable to find them.



Thalictrimine is one such BisBenzylIsoQuinoline Alkaloids which has a synonym which is now known to your Author: α-AlloCryptopine. This example has a cross-bond missing and can be drawn in several differing ways because it has a 10-membered ring, which does not necessarily adopt this twin hexagonal configuration. It could adopt a large ring shape instead, or any other shape. Collectively, they are called Protopine BisBenzylIsoQuinolines, with or without the (missing here) cross-link. Thalictrimine, besides α-AlloCryptopine has a third alias: β-Homochelidonine.


Allo, in a chemistry context, refers to a geometrical isomer, such as occurs between Cryptopine and AlloCryptopine. The former has the =O moiety nearer to the two dangling CH3-O- bonds than the N-CH3 moiety, whereas in AlloCryptopine the =O moiety is closer to the other end of the molecule.

Another way of looking at it is that the two outer moieties have swapped places.

[As far as your author knows, Cryptopine does not occur in Lesser Meadow-Rue, but AlloCryptopine does].


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Distribution
 family8Buttercup family8Ranunculaceae

 BSBI maps
genus8Thalictrum
Thalictrum
(Meadow-Rues)

LESSER MEADOW-RUE

Thalictrum minus

Buttercup Family [Ranunculaceae]

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