A pome is variously defined by students of structural botany. The most conspicuous part of the apple, pear, or quince, the best-known pome-fruits, is the outer, fleshy, edible part. This succulent part is said by some botanists to be the thickened calyx; others say that it is the enlarged receptacle. Some botanists believe that a pome consists of two to five drupe-like fruits, each drupe called a carpel, each of which contains one or more seeds. These drupes, if they are rightly so-named, are held together by a fleshy receptacle. The best definition seems to be that a pome is a fleshy fruit of which the compound ovary is borne within and connected to the receptacle. CHARACTERS OF PEAR-TREES Pome-fruits are all woody plants, shrubby or tree-like, of which the pear is always a tree. The value of the variety and the recognition of it usually depend on characters of the fruits, but the trees are nearly as distinct as the fruits, are always helpful in identification, and in the absence of fruit must be relied upon to identify a variety. Also, and even more important, the pear-grower must know whether the plant is manageable in the orchard, for which purpose he must have a description of the chief characters of the tree. _Size and habit of tree._--Size of tree is a very reliable character to determine varieties of pears. The Winter Nelis pear is dwarf as compared with other pears. Size varies greatly with environment, it must be remembered in using this character. The terms _large_, _small_, and _medium_ are commonly used to designate size. Vigor, which may be defined as internal energy, must not be confused with size. Small trees may be as vigorous as large ones. The term _habit of growth_, as used by pomologists, has reference to the form of the top. In describing the tops of pear-trees a number of self-explanatory terms are used, such as _pyramidal_, _upright-spreading_, _drooping_, _tall_, _low_, _dense_, _open-topped_, and _round-topped_. Many if not most varieties of pears may be told by the form of the top. One can tell Bartlett or Clapp Favorite at a glance by their upright branches; as one can, also, Beurré d'Anjou and Beurré Superfin by their wide-spreading branches; or Winter Nelis pear by its drooping branches. Depending upon the form of the top, a variety is easy or difficult to manage in an orchard. _Constitutional characters._--Hardiness, productiveness, susceptibility to pests, adaptability to diverse soils and climates are vaguely supposed to be dependent on the constitution of the tree. Pomologists very generally refer to these characters as constitutional. They speak of the constitution as the aggregate of the vital powers of a variety.