A third species--the Long Prickly-headed Poppy (_P. Argemone_), also known as the Pale Poppy, is a small, weak plant, seldom exceeding nine inches in height, with leaves divided into a few narrow segments. The flowers are of a pale red colour, usually less than two inches in diameter; and, like those of the commonest species, have usually a dark patch at the base of each petal. The fruit is narrow-oblong, tapering below, in fact, almost club-shaped, and is clothed with a few stiff, bristly hairs. The time of flowering is the same as that of the preceding species. [Illustration: THE COMMON RED POPPY.] In the corn-fields of several parts of England we may meet with the White or Opium Poppy (_P. somniferum_) which is largely grown in warmer countries for the opium it produces, and which was probably introduced into Britain from the Mediterranean region. It is generally about two feet in height, and quite smooth with the exception of a few spreading, stiff hairs on the flower stalks. The whole plant is of a glaucous green colour. The flowers are large, generally of a bluish white colour, often with a purple patch at the base of each petal; and the fruit is large, globular and smooth. This species flowers from June to August. [Illustration: THE WHITE OR OPIUM POPPY.] The pretty little Fumitory (_Fumaria officinalis_--order _Fumariaceæ_) is abundant in most of the cornfields and other cultivated places of most parts of Britain, flowering from June to September. It is a very variable plant, quite smooth, and of a delicate, pale green colour. Its stem varies from six inches to over two feet in length, sometimes erect, with spreading branches, but often climbing among the neighbouring vegetation, supported by the twisted leafstalks. The leaves are pinnately divided into stalked leaflets which are further cut into three-lobed segments; and the flowers are in racemes that are either terminal or opposite the leaves. At first the racemes are short, but they lengthen out considerably as upper flowers open and the lower ones fruit. Each flower has a short pedicel that arises from the axil of a whitish or coloured bract; and the two small sepals are either white or coloured like the bracts. The corolla is oblong, tubular, formed of four petals in two pairs, with a short, blunt spur at the base; and its colour is very variable--usually cream-coloured or pink, and often tipped with crimson. Some of the Mustards are very common weeds in corn-fields. They belong to the genus _Brassica_, of the order _Cruciferæ_, and are distinguished by their long siliquas, almost cylindrical in form, terminating in a 'beak' which is formed entirely of the persistent style, or of this together with a modified portion of the fruit containing one or more seeds.