Uniquely identifiable characteristics : Deep yellow flowers in the form of a spike and found in the middle and grassy margins of peat bogs and wettish moors.
Just before the fruiting stage, the closed flower can take on a resemblance to Yellow-wort but Yellow-wort grows on sand dunes, and Bod Asphodel in wet grassland bogs. Also, Yellow-wort is yellow, whereas Bog Asphodel in this stage appears deep orange.
Bog Asphodel is not an asphodel, although it was once thought to be a miniature version of one, but rather a member of the Lily Family, Alliaceae.
In Northern climes the it was once used a yellow hair dye and as a cheap substitute for saffron.
In July and August wet acid bogland can sometimes be strewn with carpets of a deep orange yellow to be replaced later in September by a carpet of orange and russet-brown as the flowers fruit.
PHYLLOERYTHRIN & 'SAUT'
Bog Asphodel is poisonous to both sheep and cattle, causing serious kidney problems and a photosensitive disorder (variously called 'alveld' in Norway;'saut' in Cumbria; and 'plochteach' 'yellowses' and 'head greet' in Scotland) caused by tri-saccaride saponins (
narthecin being the major one containing the glycosides glucose and arabinose attached to galactose,
xylosin a minor one, not shown and containing instead the glycosides glucose and xylose attached to galactose) that crystallize in the bile ducts blocking them, resulting in the accumulation of phylloerythrin (a porphyrin) that the bile ducts were attempting to discard. The photosensitization is caused by the
phylloerythrin which now permeates the blood plasma. Where the blood approaches the surface, in the skin, the phylloerythrin is exposed to sunlight, where it is photo-energized into an excited state initiating various chemical reactions in the skin, resulting in tissue damage. It is often fatal. [The Author has been unsuccessful at finding the structural formulae for either
Narthecin or Xylosin].
These same saponins (still not shown) have haemolytic and cytotoxic properties causing hepatitis, oedema and severe poisoning (usually in sheep). The two saponins are spirostanols saponins, derived by hydrolysis from furostanols which is the form in which the saponins exist in the plant.
The phylloerythrin itself was synthesized in the animal after eating green plants containing chlorophyll (another porphyrin). The chlorophyll is normally broken down in the animals gastro-intestinal tract by microbes into phylloerythrin, where it is excreted by the liver into the bile. But if the bile ducts are blocked...
BUTENOLIDES & NARTHESIDES
Bog Asphodel contains
Nartheside A and
Nartheside B, which are rather inert glucosides, but on enzymatic hydrolysis both are converted into the very same reactive aglycone, a
narthogenin, which is a lactone and has similar chemical properties to the lactones Protoanemonin and Tulipalin A. This lactone is namely 4-hydroxy-3-methoxy-2-butenolide, it doesn't appear to have a common name.
Nartheside A is (4S)-3-methoxy- 4-(D-glucopyranosyloxy)- 2-buten-4-olide, whilst that of Nartheside B is the opposite stereoisomer (4R)-3-methoxy- 4-(D-glucopyranosyloxy)- 2-buten-4-olide.