Spurge Family [Euphorbiaceae] |
status
flower
inner
petals
type
stem
toxicity
sex
13th May 2011, High Park Wood, under Whitbarrow, Cumbria. | Photo: © RWD |
A widespread creeping perennial that carpets woods and shady banks often to the exclusion of everything else. It is dioecious, with separate male and female plants. Often the carpets are exclusively of one sex. |
16th June 2009, Great Orme, Llandudno, North Wales. | Photo: © RWD |
Dogs Mercury also grows on mountains in limestone pavements since it likes base-rich soils, here sheltering in a shallow gryke. The leaves have shallow rounded teeth on them, here more prominent than is usual. |
4th May 2011, Lathkilldale, White Peak, Derbyshire. | Photo: © RWD |
Broad lanceolate and dark-green leaves. |
2nd April 2014, Yarrow Valley Country Pk, Chorley, Lancs. | Photo: © RWD |
Un-like Annual Mercury it is un-branched. Leaves, often curled when exposed to strong sun, are mainly near the top of the plant. Topped only by the flower spikes (or in this case, the fruits). These are male flowers. |
8th April 2011, Hardraw, Hawes, Yorkshire Dales. | Photo: © RWD |
Leaves have rounded teeth. The as-yet un-opened male flowers are here encased by 3 green sepals forming a triangular pyramids in small clusters up the flowering stalk. |
25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. | Photo: © RWD |
The jizz of the male plant |
2nd April 2014, Yarrow Valley Country Pk, Chorley, Lancs. | Photo: © RWD |
A male plant. As yet un-opened male flowers in several small tri-pyramidal clusters up the stalk, topped by opened flowers with numerous short stamens bearing creamy-yellow pollened anthers. |
24th April 2012, Silverdale area, Cumbria. | Photo: © RWD |
Bottom: an opened male flower with stamens and three light-green opened sepals (they lack petals). Rear of sepals displayed by top flower. The other flowers are still to open being encased in the three closed sepals forming bulging tetrahedrons. |
8th April 2011, Hardraw, Hawes, Yorkshire Dales. | Photo: © RWD |
Stamens and a sepal. Short white hairs on stalks and leaves. |
25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. | Photo: © RWD |
Packaged in tetragonal compartments formed by the three sepals are the cream-coloured anthers, at first apparently nearly spherical. |
25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. | Photo: © RWD |
The spherical anthers can be discerned packaged within this un-opened male flower (top). Middle shows the three sepals still closed up into a tetragon. Lower shows the anthers opening up releasing the cream-coloured sand-like grains of pollen which splatter the plant. |
25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. | Photo: © RWD |
Close-up of male flower with three opened sepals here displaying perhaps 11 stamens bearing anthers. |
25th March 2015, Chorley, Leeds & Liverpool Canal, Lancs. | Photo: © RWD |
Anthers opening into two parts. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
The female plants are definitely taller than the male plants. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
The female flowers are shrouded by the leaves rather than being on extended stalks towering above the leaves as are the male flowers). |
7th March 2007, near Macclesfield Forest, Cheshire. | Photo: © RWD |
The female flowers are two splayed whitish stigma. Here at least 8 can be seen from above in this photo without removing any leaves for clarity. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
Your Author removed a leaf in order to more clearly show the female flowers. They have 3 triangular green sepals, a hairy dumbbell-shaped ovary and a greenish-white two-pronged stigma. |
8th April 2017, Blackbrook, Carr Mill dam, St. Helens. | Photo: © RWD |
At least 5 female flowers can be seen on this specimen, stripped of the upper leaves hiding the flowers. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
Within the 3 sepals are 3? narrower, green 'petals'(?) (one visible in the top-most flower) |
8th April 2017, Blackbrook, Carr Mill dam, St. Helens. | Photo: © RWD |
The two-pronged style which is green below and white on top lies curled above the developing pair of hairy green balls, being the fruit. Your Author does not know what the translucent greenish tapering rods are each side of the fruit; one on the far side. The nearest appears to have a tiny bubble of water near the top. |
8th April 2017, Blackbrook, Carr Mill dam, St. Helens. | Photo: © RWD |
With the flower turned by 90° the two translucent greenish rods are now plainly visible, and both have a tiny drop of clear liquid near the top. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
The ovary swells to become the dual spherical fused fruit. |
10th June 2010, Warton area, Cumbria. | Photo: © RWD |
The fruits (which are on the female plants) are in pairs in smaller clusters up the stalk. |
25th May 2012, Grizedale area, Cumbria. | Photo: © RWD |
The fruits are fused pairs of spheres, sometimes triplets, sparsely up the stalk. |
4th May 2011, Lathkilldale, White Peak, Derbyshire. | Photo: © RWD |
Fused pairs of fruit. Unlike Annual Mercury which is hairless, the fruits have short white hairs, as do the leaves, stalks and stem. Leaf teeth are forwardly directed, and bluntly rounded. The fruit still have the two styles attached at the top. |
4th May 2011, Lathkilldale, White Peak, Derbyshire. | Photo: © RWD |
The fruits, as well as being fused to a neighbour, also have an equatorial nick, where presumably they split along when ripe to release the seeds. Both male and female flowers are petal-less and green. This is obviously a female plant with an open female flower consisting of three green sepals, an ovary topped by two short whitish styles. |
14th April 2015, Yarrow Valley Country Park, Chorley, Lancs. | Photo: © RWD |
A broken stem, this one is solid, not hollow. So your Author cut another one and that was indeed hollow. However, the clear liquid that it bled (slightly) did not eventually turn blue as it should (maybe your Author did not wait long enough?). |
17th April 2015, River Dee, Aldford, Cheshire. | Photo: © RWD |
Left. Right.
Female and Male plants, a side-by-side comparison. |
Not to be semantically confused with : Mercury ( hydrargyrum) [a highly toxic heavy-metal chemical element not present in Dog's Mercury]. Easily mis-identified as : Annual Mercury (Mercurialis annua) which differs from Dog's Mercury in being branched, and lacking any hairs, the leaves are also usually a paler green and it does not grow in extensive carpets but instead singly on bare ground. The flowers are also slightly different. Whereas Annual Mercury grows mostly in the South and East, Dog's Mercury occurs throughout the UK. Other than those characteristics, the two are very similar.
No relation to : any of the Thrives in many shaded or semi-shaded deciduous woods on either calcareous soils or on clay (which is also alkaline) where it spreads by rhizomes carpeting the ground to the exclusion of most other plants. It is a perennial and also grows on hills where it is out in the open, but there it has much more competition and occurs in just small sheltered patches. It is (mostly) dioecious, with male flowers and female flowers on separate plants, but can also be androdioecious (with male flowers on some plants, and bisexual ones on others). The carpets are usually wholly of one sex or the other, but it doesn't need to be fertilised to spread by underground rhizomes. It is more poisonous than its only other relative, Annual Mercury (Mercurialis annua), which is an annual rather than a perennial. Un-like the other members of the Spurge Family (Euphorbiaceae) it does not produce a milky sap. Fresh parts of the plant are malodorous. An unstable blue dye can be extracted from both leaves and the root, this being CyanoHermidin.
From old sources the constituents are said to include MethylAmine, (CH3)NH2, TriMethylAmine and (CH3)3N, but this plant has been little-studied. However, these two substances alone might account for the reported repugnant smell when fresh stems are broken. Newer sources do not include those substances, but instead have found some corresponding
Also found were Benzyl Alcohol,
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Mercurialis | perennis | ⇐ Global Aspect ⇒ | Euphorbiaceae |
Mercurialis (Mercuries) |
Spurge Family [Euphorbiaceae] |