SILVER RAGWORT

Senecio cineraria

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

month8jun month8june month8jul month8july month8aug

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

15th Aug 2016, Llandudno beach, North Wales. Photo: © RWD
A spreading plant growing to 1m high on cliffs, shingle (as here) and 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.


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]

Can be semantically confused with : Cineraria [a frost-sensitive pot-plant sometimes with bi-coloured ray petals in the same Asteraceae family which has a similar name but is really called  Pericallis hybrida which can grow wild 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 access in the first place although that might not be easy for plants to so do.

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. 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]