3. The formal differences between these three families are trenchant and easily remembered. The Ericae {207} are all quatrefoils, and quatrefoils of the most studied and accomplished symmetry; and they bear no berries, but only dry seeds. The Myrtillae and Aurorae are both Cinqfoil; but the Myrtillae are symmetrical in their blossom, and the Aurorae unsymmetrical. Farther, the Myrtillae are not absolutely determinate in the number of their foils, (this being essentially a characteristic of flowers exposed to much hardship,) and are thus sometimes quatrefoil, in sympathy with the Ericae. But the Aurorae are strictly cinqfoil. These last are the only European form of a larger group, well named 'Azalea' from the Greek [Greek: aza], dryness, and its adjective [Greek: azalea], dry or parched; and _this_ name must be kept for the world-wide group, (including under it Rhododendron, but not Kalmia,) because there is an under-meaning in the word Aza, enabling it to be applied to the substance of dry earth, and indicating one of the great functions of the Oreiades, in common with the mosses,--the collection of earth upon rocks. 4. Neither the Ericae, as I have just said, nor Aurorae bear useful fruit; and the Ericae are named from their consequent worthlessness in the eyes of the Greek farmer; they were the plants he 'tore up' for his bed, or signal-fire, his word for them including a farther sense of crushing or bruising into a heap. The Westmoreland shepherds now, alas! burn them remorselessly on the ground, (and a year since had nearly set the copse of Brantwood on fire just above the house.) The sense of {208} parched and fruitless existence is given to the heaths, with beautiful application of the context, in our English translation of Jeremiah xvii. 6; but I find the plant there named is, in the Septuagint, Wild Tamarisk; the mountains of Palestine being, I suppose, in that latitude, too low for heath, unless in the Lebanon. 5. But I have drawn the reader's thoughts to this great race of the Oreiades at present, because they place for us in the clearest light a question which I have finally to answer before closing the first volume of Proserpina; namely, what is the real difference between the three ranks of Vegetative Humility, and Noblesse--the Herb, the Shrub, and the Tree? 6. Between the herb, which perishes annually, and the plants which construct year after year an increasing stem, there is, of course, no difficulty of discernment; but between the plants which, like these Oreiades, construct for themselves richest intricacy of supporting stem, yet scarcely rise a fathom's height above the earth they gather and adorn,--between these, and the trees that lift cathedral aisles of colossal shade on Andes and Lebanon,--where is the limit of kind to be truly set? 7. We have the three orders given, as no botanist could, in twelve lines by Milton:--