210 THE TEACHING BOTANIST 



openings for respiration answering to stomata will need to be 

 explained to them, after they have tried to think of a use) ; 

 the leaf scars, with fibro- vascular bundles showing in number 

 answering to the number of the leaflets ; rings of bud-scale 

 scars, with a year's growth between the sets ; and the old 

 scars of fallen flower clusters. 



Under (2), the buds are terminal and axillary. 



Under (3), largest buds are toward tip, because the terminal 

 has a flower-cluster, others not, and others are larger toward 

 tip because there is more room there and more light for leaves 

 later ; lower are dormant, and even buried in bark ; ask 

 whether every leaf scar has bud in axil. 



Under (4), the shape is necessary to hold the many long 

 leaves folded up as compactly as possible. 



Under (5), brown, because there is no reason for bright 

 color, and the bud scales take the color of composition of cork 

 which happens to be brown. 



Under (6), dissection of a whole bud is needed, and draw- 

 ings of a bud laid open, and of a vertical section, or else of 

 individual leaves, scales, etc., and a flower cluster. 



Under (7), leaf origin of bud scales is shown by their 

 phyllotaxy, their anatomy, and sometimes by transitions to 

 normal leaves ; really they are the petioles, not entire leaves ; 

 in Tulip-tree, they may readily be discovered to be stipules, - 

 a beautiful case of clear morphology which all should be made 

 to work out. The wool is an epidermal outgrowth from leaves. 



Under (8), the scales form a protecting box ; resin prevents 

 rain from soaking through between them ; the wool does not 

 keep out cold altogether, but it prevents injurious suddenness 

 in changes of temperature. 



Under (9), the vegetative point with young leaves is in com- 

 mon with the others ; scales and wool are additional. 



