Not to be semantically confused with :
Fleabanes (in the genus Erigeron) [plants with similar names belonging to the same Daisy Family with similar yellow flowers, but in the case of Fleabanes, there are many more but thinner petals]
There are two sub-species :
Field Fleawort (Tephroseris integrifolia ssp. integrifolia) which is the more common, but still fairly rare. Stems 30-40cm. Less than 7 stem leaves. Phyllaries 6-8.5mm.
Field Fleawort (Tephroseris integrifolia ssp. maritima) which is much less common, very rare in fact. Stems 60-90cm. More than 6 stem leaves. Phyllaries 8-12mm.
Some similarities to : some Ragworts such as
Wood Ragwort (Senecio ovatus) but that fewer ray florets (~6) and many more stem leaves; and Broad-Leaved Ragwort (Senecio sarracenicus) but that also has fewer ray-florets (~6) and black-tipped inner bracts.
In the case of Tephroseris integrifolia ssp. maritimus, it is very rare and occurs on cliff-tops near the sea; the only place in the UK it is now found is on Anglesey.
In the case of Tephroseris integrifolia ssp. integrifolia it occurs on lime grassland in the South of the UK.
Like many plants belonging to the Asteraceae family, they contain Pyrrolizidine Alkaloids; in this instance Senkirkine,
O7-AngeloylHeliotridine. Otosenine is a rare and toxic pyrrolizidine alkaloid (actually a secopyrrolizidine diester) found in only a few plants, one of which includes Common Ragwort (Senecio jacobaea). It is an epoxide (upper left triangular group).
In all Senecio species, the primary product synthesized in the roots is
Senecionine N-oxide, which is transported to the shoots where it is transformed into particular species-specific Pyrrolizidine alkaloids (PAs) There are are well over 100 known PAs. Most are toxic apart from the non-toxic N-oxides, which are quaternary compounds, with charge separation on the same molecule due to the nitrogen taking on a fourth valence whereas normally its valency is three. However, these mainly innocuous N-oxides are easily converted within the gut of un-adapted mammals (which includes humans) into the toxic tertiary alkaloid (free base). Those mammals that have developed an evolutionary adaptation to PAs are safe from ingestion.
Innocuous Form Poisonous Form
Insects co-evolved with plants, and many have developed not only an effective defence barrier against PAs, but actively recruit and employ PAs to their advantage as a defence against being eaten by other creatures. Insects belonging to such un-related taxa as Lepidoptera, Coleoptera and Orthoptera have developed such biological adaptations to PAs. In certain Arctiid Moths the mating behaviour is modulated by PAs with the females preferring to mate with males with a high PA alkaloid concentration.
Plants and adapted insects maintain the PAs in their non-toxic N-oxide form, where they are readily converted into the toxic tertiary alkaloid inside the gut of an unadapted predator. See the Cinnabar Moth caterpillar for an example of an insect purposely ingestiong pyrrolizidine alkaloids for use as a weapon against predators.
Pyrrolizidine alkaloids are noted for their hepatotoxicity, mutagenicity, carcinogenicity and teratogenicity.