Papaver somniferum - herb and flower
"The whole plant, both leaves, stalks, and heads, while they are fresh, young, and green, yield a milk when they are broken, of an unpleasant bitter taste, almost ready to provoke casting, and of a strong heady smell, which being condensed, is called Opium." - Nicholas Culpeper
The White Poppy (oft called the opium poppy) is indigenous to Asia Minor, and is still cultivated in many parts of the world, notably Turkey, India and China, for opium, although it grows wild in many other parts of the world (In England, it grows on the cliffs on the south coast around Dover).
Culpeper described the plant in his famous Culpeper's Herbal as having
...four or five whitish green leaves lying upon the ground, which rise with the stalk, compassing it at the bottom of them, and are very large, much cut or torn on the edges, and dented also besides. The stalk, which is usually four or five feet high, hath sometimes no branches at the top, and usually but two or three at most, bearing every one but one head wrapped up in a thin skin, which bows down before it is ready to blow, and then rising, and being broken, the flowers within it spreading itself open, and consisting of four very large, white, round leaves.
This is as good as any description I could give - the plant is certainly quite a monster to anyone familiar with the
wild poppy (aka
corn poppy) of
Northern Europe, growing sometimes as high as six feet. The leaves are ragged in appearance, and the flower stalks are 3 - 4mm thick, covered in coarse hairs. The flowers themselves are large, up to four inches across, and vary quite widely in colour, often having a
lilac tinge, and ranging to quite a
pretty pink, tinged with violet at the centre of the flower.
Their rough, lanky appearance makes them ideal for the more random and wild cottage garden, and they certainly add a splash of colour at the back of a border. They grow in almost any soil, even the poorest, although my experience suggests that open soils help them to do better.
Cultivation
White poppies were first grown commercially in the UK in 1794, by one John Ball of Williton. His goal was to produce opium for use by apothecaries - laudanum as well as opium were in a great deal of demand. Both drugs were available for sale, quite legally, until the early 20th Century - Harrods of London openly sold heroin and opium until anti-drug laws were passed during the First World War!
When cultivated for medicine, the plants are allowed to mature and produce their fruit - large, three-quarter-spherical green, bulbous affairs around an inch (25mm) diameter. When cut, these ooze a latex-like susbtance containing a variety of alkaloids, principally morphine, but also narcotine, codeine, thebaine, narceine, papaverine, codamine and rhoeadine.
The flower gardener will dead-head the flowers once they are finished, to encourage new flower growth, the flower arranger will allow the heads to dry to leave a large mid-brown "pepper pot" head, sometimes slightly ribbed along the sides, the top having the delightful appearance of a small gear cog, from which the poppy seed may be shaken.
The crop is not much grown for medicinal use in Europe now, most sources of pharmaceutical opium being Far Eastern countries.
The white poppy is also connected with the more traditional, red Remembrance Poppy, and represents a call for peace as well as remembrance - see bipolarbear's writeup on that topic.
Encyclopædia Britannica
http://www.bibliomania.com/2/1/66/113/21157/1/frameset.html
http://www.botanical.com/botanical/mgmh/p/popwhi64.html