XV] LENTICELS 123 



Rhus Bittersweet lane 



Ailanthus Buckthorn Plum 



Virginian Creeper Cherr y Lime 

 Bird Cherry. 



Definite lenticels appear to be absent from the twigs 

 of the Vine, Syringa, Clematis and Honeysuckle, and they 

 are small and inconspicuous in 



The lenticels are sometimes visible on the shoots, as 

 we have seen, but they are not usually conspicuous until 

 the twig is fully matured, and often not until the second 

 or third years. In some plants, e.g. Cherry, Bird Cherry, 

 Birch and Hazel, they are transversely extended as the 

 branch thickens, and may form lung lines extending hori- 

 zontally round the stem ; in others, e.g. Buckthorn, they 

 extend longitudinally but not to any considerable degree. 

 They are often pale in colour, but not always, and the 

 contrast colours with that of the twig are occasionally 

 marked. 



