_The core._--The position of the core in the fruit is often a valuable means of distinguishing varieties. If close to the stem, the core is said to be _sessile_; if at the center of the pome, it is _median_; when distant from the stem, _distant_. The cell containing seed, called a carpel, is morphologically a modified leaf, which, by folding together and by union of its edges forms a closed receptacle. In some varieties, the carpels are _open_; in others _closed_. If the tip of the carpel is indented, it is said to be _emarginate_; if long and pointed, _mucronate_. In shape, carpels may be _round_, _cordate_, _obcordate_, _elliptical_, _oblong_, _elongated_, _ovate_, or _obovate_. In the cores of most pomes there is a central cavity called the _core cavity_, sometimes spoken of as the _axial sac_ which may be either _narrow_, _wide_, or _lacking_. This is a character of much importance and reliability in pears. When the carpels extend quite to the axis of the fruit, they are said to be _axile_ and there is no core cavity; when distant from the axis, they are _abaxile_ and a core cavity is formed. Sometimes the carpel is lined on the inner surface with a white substance, when it is said to be _tufted_. In some pears, there are many fine hairs in the core-cavity in which case the cavity is said to be _tufted_. The limits of the core are marked by a line in most pome-fruits--usually very distinct in apples and quinces--which in most varieties of pears is indistinct. The area enclosed by this line may be large or small and may be variously shaped. When the core-line joins the calyx-tube along the sides, it is said to be _clasping_; when the two ends of the line meet at the base of the calyx-tube, the expression _core-lines meeting_ is used. The core-line in pears is nearly always, if not always, clasping and very often it is a more or less thickened area of grit-cells. _Seeds._--Seeds are characteristic in all varieties of pears and might well be used more generally than is the case in classification. The number is exceedingly variable in different varieties. The usual number is two in each cell, but often there are three or more and occasionally they are missing. Seeds vary greatly in different varieties in size, shape, and color, and differences in these characters are as constant as are those of any other organ of the fruit. Number, size, shape, and color of seeds should be noted with care in every technical description of a pear. The point of the seed, also, is worth noting; it may be _acute, acuminate_, or _obtuse_. Like the carpels, the seeds are often _tufted_. There are several so-called seedless pears, but all of these occasionally contain some seeds. Very often seedlessness is brought about by lack of proper pollination. An occasional fruit without seeds is found in nearly all varieties, but these fruits are usually more or less abnormal in size or shape.