Would you create for yourself by the study of nature a source of enjoyment equally pure and inexhaustible, adopt a method of classification for your own use, and, to facilitate you in the task, take for your types those plants which are at once the commonest and most characteristic of each season. Quite at your ease, you may begin your analysis by examining the parts which, like the calyx and the corolla, most attract your attention. The most rational plan, however, would be, to commence with the seed, and to follow it through all the wonderful phases of its life, from the development of the embryo to the maturity of the fruit. Unfortunately, we are all compelled to take time into account; time is so much more precious than money,--it is the measurement of our existence. Undoubtedly, the mind, with its gigantic strides, like those of an Homeric god, tends to overleap the confines both of time and space. But the senses, without whose co-operation the intellect could not create science, never fail to remind us that we are, alas! but mortals. By this incessant appeal to order, we are under the necessity of doing, not what we _would_, but what we _can_. And the part we really play is, consequently, much more modest than that which we love to imagine ourselves as playing. But to return to our flowers. * * * * * What see you in the little centaury which you hold in your hand? (Fig. 56.) In the first place, a corolla with five petals of a delicate rose-hue, very pleasant to the sight. Take care! those foliola are not _petals_, if you give that name to the free parts of the corolla. Look at them thoroughly. Your foliola are prolonged at their base in a narrow tube, which is easily removed. If you had begun here,--if, instead of proceeding from the top to the bottom, you had, in your analysis, proceeded from the bottom to the top, you would have acquired a wholly different view of things. You would have said that the corolla is tubular, greenish, with a rosy limb, deeply divided into five lobes. And in so doing, you would have run no risk of deceiving yourself. The indications given by Nature herself are the most precious; they are the lessons of a teacher who cannot err: never pass them by with indifference or neglect. In your study of the different parts of a vegetable, follow, as far as possible, the actual movement of the sap. [Illustration: FIG. 56.--The Common Centaury.] The calyx of our gentian has, like its corolla, the form of a five-divided tube; which, indeed, is one of the usual characters of the Gentian family.