13 



XVII. Trees. 



1. Common Name, Scientific Name, and Family. 



2. The tree from a distance in early spring- or winter. 



(a) The contour, habit of growth, or general outline of the tree, 

 whether pyramidal, spreading and rounded, pillar-like, symmetrical, or 

 one-sided. 



{h) The color of the foliage. 



3. The tree at close quarters. 



(a) Trunk. Circularity, straight or crooked, or tapering^, excurrent 

 deliquescent, indications of disease or decay, size. 



(b) Bark. Rugged or smooth; brown, gray, or silver white; any 

 tendency to peel off in scales or come off ; any lichens, moss or fungi. 



(c) Branches. Whether inclined to the stem at an acute or obtuse 

 angle; general difference between upper and lower branches; whether 

 drooping, or have an upward trend or a downward curve; whether the 

 tw^igs are one-sided, or on both sides of the main branch; whether alter- 

 nate or opposite. 



{d) Twigs. Whether crooked, rough-barked, indicating slow 

 growth ; or straight, smooth-barked, indicating quick growth ; study of 

 transverse section of twig, noting bark, wood and pith and annual rings 

 and medullary rays ; examine the buds, and note their relative positions, 

 shape, color, scales, rudimentary leaves and flowers ; relation of bud ar- 

 rangement to branching, and the branching to the ultimate form of the 

 tree ; study of leaf-scars ; study of bud-scale rings and age of the tree. 



XVIII. The Woods of Dicotyledonous Trees. 



1. The object of this study is the identification of the woods of our 

 common trees. Transverse sections of twigs i^ to f inch or more should 

 be made, and with the aid of a lens determine (1) whether there is any 

 diffrence in density between the spring and the autumn woods ; (2) 

 whether the vessels are distinctly visible or hardly visible ; (3) whether 

 the medullary rays are wide and quite visible to the naked eye ; (4) the 

 color of the wood and medullary rays. 



2. Make diagrammatic sketches to illustrate the difference between 

 the various woods. 



3. Study the specimens in the laboratory. 



4. Try and make a key by means of which the woods can be iden- 

 tified. 



XIX. The Development of the Apple and Cherry. 



This Involves a study of the ovary and its changes during the for- 

 mation of the fruit. Sections of different specimens should be made 

 at frequent intervals, and a series of drawings, kept with their accom- 

 panying dates. 



