Some similarities to : Henbane, a member of the same family, but that has larger flowers where the petals are rounded rather than pointed.
Superficial resemblance to : Potato (the leaves)
Uniquely identifiable characteristics
Distinguishing Feature : The large black berries or the green to dark-purple bell-shaped flowers.
No relation to :
Alpine Enchanter's Nightshade (Ciracea alpina) or
Enchanter's Nightshade (Ciracea lutetiana),
Upland Enchanter's Nightshade (Ciracea × intermedia), [plants with similar names belonging to a differing family].
The only plant in its genus, Atropa, but other Nightshades are related:
Leafy Fruited Nightshade (Solanum saracoides),
Small Nightshade (Solanum physalifolium),
Green Nightshade (Solanum physalifolium var. nitidbaccatum) Woody Nightshade (Solanum dulcamara), and Black Nightshade (Solanum nigrum) and all are poisonous to some degree but not as much as Deadly Nightshade.
It grows in old quarries, on scrub and waste ground but always on lime. The very poisonous berries are green at first turning black, large and presented singly still within the five green sepals in which the flowers used to snuggle. Ingestion of 10 to 20 berries is sufficient to kill an adult, but a quarter of that for a child and where just 2 berries can cause symptoms to appear. Consumption of just 0.3gram of the leaves (corresponding to a single leaf) is toxic.
All parts of the plant contain dangerous quantities of Tropane alkaloids, but the roots contain most.
Hyoscyamine (aka daturine) is the main toxin and is the laevorotatory stereoisomer to Atropine which is the dextrorotatory counterpart. Scopolamine, another tropane alkaloid, is a minor component. These alkaloids, if ingested, cause dilation of the pupil of the eye. Since women look more attractive with wider pupils, this plant was often used cosmetically by women up until the Renaissance period to dilate their eyes, hence the plant became known as 'belladonna', a name which has subsequently been subsumed into its scientific name. The first part of its name, Atropa, gives rise to the name of the alkaloid found within it, Atropine. laevo-atropine has been used in medicine as a mydriatic to dilate the pupils for eye examinations, etc.
Scopolamine has been used in pills for travel sickness and to alleviate the analgesic effects of opioid analgesics. The two are antidotes for each other.
Rabbits and cattle are seemingly immune to the toxins able to eat it without noticeable ill effects. The amount of toxins within the plant is subject to vary quite a lot.
The plant has been used as an arrow poison. A feeling of being able to fly and other hallucinogenic experiences was experienced by rubbing the leaves on the skin, especially on sensitive areas of the skin where it is thinner. Thus began the depiction of witches on brooms flying across the landscape.
Belladonnine is found in the acuminata variety of Deadly Nightshade (Atropa belladonna var. acuminata) which does not seem to occur naturally in the UK. Belladonna, although not a dimer, has two units of the Tropane moiety (the moiety with the nitrogen atom on the left). It has most similarities to Atropane, which is also found within the Deadly Nightshades. Both are toxic principles. Belladonna can be synthesized from Atropine by warming with Hydrochloric Acid, HCl.