Railroad building and other stories

“Right. Well, the parallel-veined leaves belong to the sort of plants which have only one seed-leaf or cotyledon, and we call them monocotyledonous plants; and the netted-veined leaves belong to and distinguish those with two cotyledons, and are called dicotyledonous plants. Now notice that a leaf has three parts: a blade, the broad thin part, a petiole, or, as you would call it, the stem-stalk, which supports it; and, as you see in these quince leaves, there is also a pair of small leaf-like appendages which are called stipules. All leaves do not have these, and some have no petioles. In such cases we say the leaf is sessile, and sessile means sitting; and we shall find the word used in regard to other parts of the plant as we go on in our study. This quince, and also the apple leaf, have one large vein running through the middle as if the petiole were extended to the tip or apex of the leaf. This sends off branches, and these in turn break into smaller ones until the leaf is all over network. It is tilled in with a green pulp and covered with a thin skin called the epidermis.”“Why, we had that word in physiology,” exclaimed one of the listeners. “It means the same as cuticle or outside skin.”“Exactly; so you see we have in the blade the fibrous framework or skeleton, the pulpy filling, and the transparent covering.”Charlie had been listlessly fingering a leaf, seemingly not interested in the talk, but at this moment he started up, exclaiming, “I know how to make skeleton leaves! You just put the leaf into some kind of acid—I have forgotten the name, that eats out the pulp and leaves the framework—sister Anna has a whole lot of them.”“Yes; and if we had one here we could see the method of veining very plainly. In the parallel-veined leaves all the larger ribs run lengthwise, and there are no branching veins which you can see plainly, only very small vein-lets...