PRIMARY ARRANGEMENT. 22 5 



be reproduced here, had to be described above, and may be there referred to 

 if necessary. Peculiarities, which depend upon the tissues covered by it, will be 

 noticed when the latter are treated of. 



As regards the other forms of tissue, to be dealt with in this section, we may 

 refer in the first place to the method of grouping given on p. 5, which holds for all 

 tissues. It may here be added that a group of tissues bordering directly on the 

 epidermis is called from its position hypodermal, while distinct hypodermal layers are 

 indicated by the substantive hypoderina ^ 



It is best to begin the description of the primary arrangement of tissues with the 

 tracheae and sieve-tubes, since these are connected, in almost all plants with which 

 W'e shall be engaged, into strands or vascular bundles ; and these form a well-marked, 

 uniformly comparable skeleton, on and around which the other tissues arrange 

 themselves. 



' Pfitzer, Pringsheim's Jahib. Bd. VIII. 



