The peculiar arrangement of the stamens above described is sufficient in itself to distinguish the genus _Salvia_ from all the other Labiates, and the importance of the peculiarity in connexion with the pollination of the flower is so interesting that we may well spend a few minutes in studying it before passing on to other species. In the first place it should be mentioned that the stamens of _Salvia_ are mature before the stigma, and that, as a consequence, self-pollination is impossible. The lower, abortive anthers of the two stamens are joined together and form a little valve which closes the throat of the corolla tube. Each one, however, has a notch in its inner side, and the two notches, meeting in the middle, form a little hole. When a bee visits the flower, it alights on the lower lip of the corolla, and thrusts its tongue through the hole to reach the nectar at the base of the tube. In doing this it pushes the abortive anthers backwards, and the upper, fertile anther cells, which rest under the arched upper lip, are thus made to swing downwards and forwards so that they touch the bee's back; and, if they are ripe, to deposit some pollen. After the pollen has been thus removed, the style lengthens and curves downward, bringing the stigma, which is now mature, to the position previously occupied by the fertile anther cells at the time they were made to swing downwards by the bee. Thus, if a bee which has previously visited a flower with mature anthers now comes to one in which the stigma is ripe, the pollen dusted on its back by the former is rubbed against the stigma of the latter, and cross-fertilisation is the result. [Illustration: SECTION OF THE FLOWER OF _Salvia_. 1. Stigma--not yet mature. 2. Stamen.] [Illustration: THE SELF-HEAL.] The Common Marjoram (_Origanum vulgare_) is an aromatic plant that often grows in great abundance on dry hilly pastures, especially in limestone and chalky districts. Its stem is thin and hairy, a foot or more in height; and the leaves are stalked, ovate, blunt, slightly toothed, downy, and about an inch in length. The flowers, which bloom from July to September, are of a rosy purple colour, in numerous globular clusters, the whole inflorescence forming a leafy panicle. The overlapping bracts are about as long as the calyx, and usually tinged with red or purple; the calyx has five, short, equal teeth, and is very hairy in the throat; the corolla is about twice the length of the calyx, and has four lobes, the upper of which is a little broader than the others; and the stamens are in two pairs, one pair longer than the other. It will be noticed that some of the flowers are larger than others, and that these are perfect, while the smaller ones have no stamens.