Poppy, in botany, a genus of plants known botanically as pa paver, the type of the family or natural order Papaveraceae. They are annual and perennial erect herbs containing a milky juice, with lobed or cut leaves and generally long-stalked regular showy flowers, which are nodding in the bud stage. The sepals, very rarely three, which are two in number, fall off as the flower opens, the four (very rarely five or six) petals, which are crumpled in the bud stage, also fall readily. The numerous stamens surround the ovary, which is composed of 4 to 16 carpels and is surmounted by a flat or convex rayed disk bearing the stigmas. The ovary is incompletely divided into many chambers by the ingrowth of the placentas which bear numerous ovules and form in the fruit a many-seeded short capsule opening by small valves below the upper edge. The valves are hydroscopic, responding to increase in the amount of moisture in the atmosphere by closing the apertures. In dry weather the valves open, and the small seeds are ejected through the pores when the capsule is shaken by the wind on its long stiff slender stalk. The flowers contain no honey and are visited by pollen-seeking insects, which alight on the broad stigmatic surface. The genus contains about 40 species, mostly natives of central and south Europe and temperate Asia. Five species are British; P. Rhoeas is the common scarlet poppy found in cornfields and waste places. Cultivated forms of this, with exquisite shades of colour and without any blotch at the base of the petals, are known as Shirley poppies. P. somniferum, the opium poppy, with large white or blue-purple flowers, is widely cultivated (see Opium). The Oriental poppy (P. orientale) and its several varieties are fine garden plants, having huge bright crimson flowers with black blotches at the base. Many hybrid forms of varying shades of colour have been raised of late years. The Iceland poppy (P. undicaule), is one of the showiest species, having grey-green pinnate leaves and flowers varying in colour from pure white to deep orange-yellow, orange-scarlet, &c. Specially fine varieties with stalks 18-24 in. high are cultivated on a large scale by some growers for market. The Welsh poppy belongs to an allied genus, Meconopsis; it is a perennial herb with a yellow juice and pale yellow poppy-like flowers. It is native in the south-west and north of England, and in Wales; also in Ireland. The prickly poppy (Argemone grandiflora) is a fine Mexican perennial with large white flowers.
To the same family belongs the horned poppy, Glaucium luteum, found in sandy sea-shores and characterized by the waxy bloom of its leaves and large gcilden-yellow short-stalked flowers. Another member of the family is Eschscholtzia californica, a native of western North America, and well-known in gardens, with orange-coloured flowers and a long two-valved fruit pod.
The plume poppy (Bocconia cordate and B. microcarpa) are ornamental foliage plants of great beauty. The cyclamen poppy (Eomecon chionantha) is a pretty Chinese perennial, having roundish slightly lobed leaves and pure white flowers about 2 in. across. The tree poppy (Dendromecon rigidum) is a Californian shrub about 3 ft. high, having golden-yellow flowers about 2 in. across. The Californian poppy (Platystemon californicus) is a pretty annual about a foot high, having yellow flowers with 3 sepals and 6 petals; and the white bush poppy (Romneya Coulteri) is a very attractive perennial and semishrubby plant 2-8 ft. high, with pinnatifid leaves and large sweet scented white flowers often 6 in. across.
