14 BOTANY. 



Exercise 8. 



13. Comparison of leaf arrangement. Study the arrangement of the leaves 

 on several different shoots, by an examination of the leaf scars or by the buds. 

 The teacher can select shoots which represent several different systems of 

 phyllotaxy, for example the opposite and the alternate; among the alternate 

 let the pupil determine those which have the angles of divergence repre- 

 sented by the fractions , i, f, f, etc. 



Exercise 9. 



32. Field observations on trees and shoots. If the weather is favorable 

 an excursion to the woods, fields, or to some park or garden would be an ap- 

 propriate conclusion to these exercises. The result can be made the basis of 

 a short paper by each student. For example, let the pupil observe the habit 

 (that is, the general form, character of branching, etc.) of different trees ; the 

 character of the bark ; any further peculiarities of buds and shoots ; the dif- 

 ferences between deciduous trees (those which shed all their leaves in the 

 autumn, or whose leaves die), and evergreens. (In the evergreens the leaves 

 remain green and attached to the trees for more than a year, for example in 

 the pines for about three years. In this way while new leaves are formed 

 each year, and old leaves are shed each year, there are green leaves on the 

 tree at all seasons.) 



Material (for exercises 5-8). Shoots showing two or three years' growth 

 of the following species (or others which may be more convenient in some 

 localities) : horse-chestnut, birch, dogwood, apple, peach, etc., a selection 

 to represent several different types. In selecting some of the shoots it will 

 be well to collect some which have borne fruit and which have fruit buds, in 

 order to compare the different type of branching induced on the fruit-bearing 

 shoots. (If some of the material can be collected when the leaves are present 

 and preserved, such leafy shoots will be interesting for comparison, especially 

 shoots of the birch, which have short lateral branches bearing only two 

 leaves each year.) 



