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]
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.
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.