SILVER RAGWORT

Senecio cineraria

(Alternative name: Jacobaea maritima)
Daisy & Dandelion Family [Asteraceae]

Flowers:
month8jun month8june month8jul month8july month8aug

Pappus: pappusZpossible (white, simple)
pappus8jul pappus8july pappus8aug pappus8sep pappus8sept pappus8oct

status
statusZneophyte
flower
flower8yellow
inner
inner8orange
morph
morph8actino
petals
petalsZMany
stem
stem8round
toxicity
toxicityZhigh
sex
sexZbisexual

15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
A spreading plant growing to 1m high on cliffs, shingle (as here) or on rough ground especially near the sea (as here amongst Sea Sandwort).


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Leaves are silvery with densely-matted hair.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Almost every part but the flowers covered in dense matted silvery-white hairs. Flowers with both disc and ray florets.


15th July 2009, Rufford, Lancs. Photo: © RWD
Disc florets are a deeper yellow than the ray florets.


15th July 2009, Rufford, Lancs. Photo: © RWD
Stigma has two curled-over styles.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Disc florets opening and stigma extending. Ray florets with 2 notches (being 3 flowers).


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Even the phyllaries surrounding the flower are densely silvery-woolly.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Flowers finishing for the season.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Finished flowers. Fruit brown, achene cylindrical.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
The densely matted hairs.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Leaves oval to oblong and deeply pinnately lobed.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Stems woody near the base.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
Leaves are less densely hairy on the top surface, often with green showing through.


15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
But densely hairy on the underside.




ANOTHER SPECIMEN

This one appears whiter (perhaps a cultivated variety?)

23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
A shorter specimen but which is less greenish and more greyish-white


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
The dense white hairs on the leaves do wear off though revealing a dull-green beneath [These might be the underside of the leaves?).


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
There are between 10 to 13 ligules (aka petals or ray-florets) on each flower - which are between 3 to 6mm long, although there are some florets still yet to open and which show no signs of the outer petals... yet.


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
On the lowest flower, which has not yet fully opened, the ligules have not yet fully grown and can be seen as short, furled up petals surrounding the as-yet unopened disc florets in the centre.


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
The now brown spent disc flowers with a few of their anthers and/or stigmas showing.


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
The spent florets have mostly departed leaving these with their numerous but still compacted white parachute hairs (pappii) still to be released into the wind.


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
Their numerous parachuted seeds (seeds not yet visible - still buried deep surrounded by the white-turning-brown phyllaries).


23rd Aug 2018, Boston Castle, Rotherham, Sheffield. Photo: © RWD
Leaves radiating out from a stem and viewed from above.


Not to be semantically confused with : Silverweed (Argentina anserina), Silverbole Pine (Mobilus telegraphicus darlingtonii), Silver Birch (Betula pendula), Silver Holly (Ilex aquifolium), European Silver-fir (Abies alba), Silver-leaved Lime (Tillia tomentosa), Silver Lady's-mantle (Alchemilla conjuncta) or Silver Maple (Acer saccharinum) [plants with similar names belonging to differing families] nor with   Silver [a metallic transition element]

Nor with Cineraria (Pericallis hybrida), a well-known but frost-sensitive pot-plant with daisy-like flowers in the Asteraceae family but the colour of the rays are red, pink, purple or blue. A plant which only occurs naturalised in warm frost-free areas such as West Cornwall, Isle of Man and and the Scilly Isles.

Hybridizes with : Common Ragwort (Senecio vulgaris) to produce Senecio × albescens can occurs wherever Common Ragwort is found except the Channel Islands. It is intermediate in hairiness, leaf-shape and habitat but has hairy disc-achenes (seed parachute hairs) as does Common Ragwort.

Also hybridizes with Hairy Ragwort (Senecio erucifolius) to produce Senecio × thuretii but which is far rarer than the above hybrid, being found in East Kent in 1978. It differs from Senecio × albescens in that it has a supplementary and much shorter (a quarter the length) of the main phyllaries surrounding the flower.

Silver Ragwort has a salt-tolerance similar to that of Halophytes, which enables it to preferentially grow near the sea. However, it is not a salt-includer like is Common Glasswort, but rather a salt-excluder, with mechanisms for either expelling salt or not allowing it ingress in the first place - although that might not be so easy for some plants to avoid.

PYRROLIZIDINE ALKALOIDS

Like other Ragworts, Silver Ragwort also contains a mixture of mostly toxic Pyrrolizidine Alkaloids (although some are more poisonous than others): Florosenine 32%, Otosenine 24%, Floridanine 2% and Doronine 1.5%. Others detected are Senecionine, Seneciphylline, Integerrimine, Jaconine and Jacobine, all at a concentration of about 0.1%. But others have observed great differences in concentrations of pyrrolizidine alkaloids within Silver Ragwort presumably highly dependent upon soil conditions.


Despite their name, neither Florosenine nor Floridanine contain fluorine (nor chlorine for that matter.


It should be noted that both Jaconine and Doronine contain an atom of chlorine, which is highly unusual in plants, but perhaps to be expected for a plant which grows near the sea in saline conditions. The chlorine atom (shown in green) thus makes these pyrrolizidines Organochlorides and exceptionally toxic, much more so than they otherwise would be. The only difference between the two is the extra O-acetyl moiety at the top right of Doronine. Doronine also occurs in Chamois Ragwort (Senecio doronicum) [which must not be confused with Leopard's-Banes being species of Doronicum] and also occurs in Doronicum macrophyllum, but the latter does not occur in the UK. See Naturally-occurring organochlorides in the Plant Kingdom


Both Florosenine (top left) and Jacobine (bottom right) [as does Otosenine - not shown here] contain an epoxy oxygen atom forming a 3-sided moiety (top left on both structural formulae) which would also tend to make these more toxic than their cousins lacking that moiety.


  Senecio cineraria  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae
 BSBI maps
genus8Senecio
Senecio
(Ragworts)

SILVER RAGWORT

Senecio cineraria

(Alternative name: Jacobaea maritima)
Daisy & Dandelion Family [Asteraceae]