PLATE XVI. 



Figs. 



1. Cochlearia Armoracia (Horse-radish). A laciniate 

 leaf. (J. Hutchinson photo.) p. 163. 

 2, 3. Thuja occidentalis (Arbor-vitae) . Fig. 2. — A twig 

 showing the adult foliage. (Mingay photo.) p. 

 176. Fig. 3. — A twig showing the juvenile foliage 

 (" Retinospora ericoides"). (Mingay photo.) p. 176. 

 4. Pinus monophylla. A short- shoot showing the reap- 

 pearance of the normally-suppressed second needle, 

 pp. 156, 222-223. 



