The fourth twig (Silver Maple) shows that the plant had opposite leaves, and supernumerary buds at the sides of the true axillary ones; the true axillary buds are smaller than those at the sides. It would, in such cases, be reasonable to suppose that the supernumerary buds were floral ones, and that the plant blooms before the leaves expand. The annual growths are quite extended; two years and a part of the third make up the entire twig. If it was cut during the winter of 1891-92, it must have had leaves on the lower part in 1889 and 12 leaves on the middle portion in 1890, as well as probably 4 on the lower portion on the side shoots. Last year it had 14 leaves on the end portion, two at least on each side shoot below, making 24 in all. _Folding of Leaves in the Bud._ There are some peculiarities in the arrangement of leaves in the bud which can be investigated only in the early spring. The common plans among trees are--_Inflexed_: blade folded crosswise, thus bringing it upon the footstalk. Tulip-tree. _Conduplicate_: blade folded along the midrib, bringing the two halves together. Peach. _Plicate_: folded several times lengthwise, like a fan. Birch. _Convolute_: rolled edgewise from one edge to the other. Plum. _Involute_: both edges rolled in toward the midrib on the upper side. Apple. _Revolute_: both edges rolled backward. Willow. _Obvolute_: folded together, but the opposite leaves half inclosing each other. Dogwood. CHAPTER VI. _The Preparation of a Collection._ [Illustration: Fig. 16.] Three specimens are needed of each kind of tree: one, a branch showing the flowers; another, showing the fruit--one of these, and in many cases both, will show the leaves. The third specimen, cut from a large limb or trunk, shows the bark and the wood. This should be a specimen with a surface so cut as to show the wood in the direction of the silver grain, _radial section_; with another surface cut in the direction of the annual layers, _tangential section_; and with a third cut across the grain, _cross-section_. It should be a specimen old enough to show the change of color in the heart-wood. By taking a limb or trunk 8 inches in diameter, all these points can be secured. A specimen cut as shown in the figure will illustrate all the desired points. Side E F G shows sap-and heart-wood in tangential section; side A B D C shows the same in radial section; end A B F E, in cross-section; and B F G D shows the bark. The central pith is at I; the heart-wood extends from C to J; the sap-wood from J to D. The silver grain is well shown at the end, and the blotches formed by it on the radial section. By having the piece made smooth, and the upper part down to the center (H) varnished, the appearance of the wood in furniture or inside finish will be illustrated.