Another wild cherry, generally known as the Gean (_P. Avium_), is still larger, sometimes reaching a height of thirty feet, and is not uncommon in woods and hedges. The bark is smooth; the leaves abruptly pointed, soft, drooping, and downy beneath; and the beautiful white flowers are in almost sessile umbels. The calyx-tube of this species is contracted at the mouth, and the fruit is either red or black, heart-shaped, and bitter. The leaves turn to a deep red colour in the autumn. Among the earliest flowers of Spring are the white blossoms of the Sloe or Blackthorn (_Prunus spinosa_), which appear in March and April, some time before the leaves. The shrub grows from four to eight feet high, has a blackish bark, and numerous branches, the smallest of which terminate in hard, rigid thorns. The leaves are ovate, finely-toothed, smooth, stalked, with small, free stipules. The flowers are small, shortly-stalked, with a free, deciduous calyx of five lobes; five spreading petals; from fifteen to twenty stamens; and an ovary which ripens to an almost black, juicy, acrid drupe, about half an inch in diameter, containing a hard stone, and covered with a bluish bloom. This shrub is very common in thickets and hedgerows. The Bullace (_Prunus insititia_), sometimes regarded as a variety of _P. spinosa_, is a very similar bush, growing in similar situations, and flowering at the same time; but its bark is brown, and the branches less spiny. Its leaves, also, are downy beneath; and the flowers, which appear at the same time as the leaves, are in pairs, on downy stalks. The fruit is about double the size of that of the last species, either dark or yellow in colour, less acrid, and drooping. The above two species are the origins of the damsons and plums of our fruit gardens. The May or Hawthorn (_Cratægus Oxyacantha_) is so well known that there would be no necessity to describe it, were it not for the fact that, being so familiar, its distinguishing characters are liable to be overlooked. It is a much-branched shrub, with many of the branches modified into protective spines. The leaves are simple, smooth, deeply-lobed and obtuse, have deciduous stipules, and appear before the flowers. The flowers are generally white, sweetly-scented, and arranged in corymbs. There are five sepals and five petals, and the numerous stamens have pink anthers producing brown pollen. The carpels, one to three in number, are enclosed in the calyx-tube; and the fruit is a bright red pome with a bony core.