230 PRACTICAL BOTANY 



it follows that they are produced at the upper end of 

 each annual increment. 



Examine the buds at the apices of the stem and 

 branches : they are covered with brown scale-leaves : 

 thus a distinction is to be drawn between protective 

 scale-leaves, and the foliage-leaves. 



There is considerable variety in the character of the non- 

 reproductive leaves of the Coniferw, though the form of the 

 individual leaf is simple throughout the series. In some cases 

 only green foliage-leaves are developed, as in A raucaria, Juni- 

 perus, Thuja; in Phyllocladus only scale-leaves are produced, 

 while the flattened stems assume the assimilative function ; in 

 other cases, as in Taxus and A lies, there is an alternation of scale- 

 leaves which protect the bud, and foliage-leaves ; in Pinus 

 sylvestris, the somewhat complicated shoot of which will be 

 described in detail below, there are both scale- arid foliage-leaves, 

 the former alone being borne on the stronger axis of unlimited 

 growth, while the latter (together with scale-leaves) occur only 

 on the foliage -shoots of limited growth (bifoliar spurs). Specimens 

 of different genera of the Coniferce should be examined and 

 compared. 



B. Take a branch of Pinus sylvestris, cut in autumn, 

 including at least four years' growth. 



N.B. The limits of each year's growth may be recognized 

 externally at those points where false whorls of strong lateral 

 axes are developed ; and the portion of stem lying between two 

 such whorls may be regarded as roughly representing one year's 

 growth. 



T. Consider first the growth of the year in which the 

 branch was cut, i.e. the part above the youngest whorl 

 of lateral axes. At its apex is a large bud, surrounded 

 by a variable number of smaller lateral buds. 



From a bud, which has been treated with alcohol to 



