In your summer-walks, dear reader,--summer-walks through green lanes rejoicing in the shade of over-arching elms, or along woodland glades, carpeted with odorous turf,--you must frequently have met with an herbaceous plant, whose purple-blue flowers, arranged in regular succession, form the prettiest coloured cones imaginable at the extremity of the stem and branches. To this plant, the self-heal, we shall return immediately. Perhaps you have passed it by somewhat indifferently, for we pay little heed to common things, and on the threshold of woods, and in their winding avenues, the self-heal is very common. The celebrated German botanist, Bock (or Tragus) bestowed upon it, two centuries before the epoch of Linnæus, the name of _Prunella vulgaris_. The specific appellation, _vulgaris_, is here employed very appropriately, but we should commit a grave error if we supposed every species qualified as _vulgaris_ to be "common." For example, the _Lysimachia vulgaris_, a species of Primulaceæ, is far from being found everywhere. Pray, take the trouble to pick one lowly specimen; being specially careful to take up the whole plant, stem, root, and branch. Lying along the ground, it seems larger than it really is. Its root is a creeper; at the level of the insection of the leaves some small shoots project, the fibrous radicles which compel the lower part of the stem to crawl like the bugle, _Ajuga reptans_. Does the prunella belong to the family of Labiatæ, like the bugle? [Illustration: FIG. 49.--The Prunella.] See for yourself. The stem is quadrangular; the branches and leaves composed of two lips. The stamens are four in number, two of which are longer than the others; finally, by means of a lens, you can easily distinguish, at the very bottom of the calyx, four tiny seeds (a _tetrachænium_) grouped around the style. These features indicate that our plant belongs, in effect, like the bugle, to the Labiatæ family. But mark the difference. In the bugle, as in all the species of the same genus (_Ajuga_), as well as in all the _Teucriums_--of which wild sage (_Teucrium scorodonia_) is the most widely-diffused type--in all the Labiatæ, the corolla is apparently _unilabiate_,--that is to say, the upper lip is so shortened that only the lower is prominently visible. This is not the case with our self-heal: it is distinctly bilabiate. The upper lip of the corolla here forms a positive _hood_, sufficiently ample to protect the didynamous stamens (two long and two short), as in Fig. 50, _a_; the lower lip is three-lobed, and the central lobe is largest of the three. By separating the two lips, you can see the two short stamens fixed to the base of the lower one, and the two long attached to the central part of the upper. (See Fig. 50, _b_.) [Illustration: FIG. 50.--The Lips of the _Prunella vulgaris_.] Let us pursue the analysis of the flowery cone you hold in your hand.