110 



SCIENTIFIC AGRICULTURE. 



ducts, the same as that of exogens. The cellular tissue exists 

 equally in all parts of the plant; the rest are in bundles, im- 

 bedded in the stem: "each bundle consists of one or more 

 ducts, with spiral vessels adjoining their inner side next to the 

 centre of the stem, and woody fibres on the outside, as in the 

 exogen. 



" A new set of these bundles is formed annually, or oftener, 

 proceeding from the leaves, and passing downwards in the 

 central parts of the stem, where the cellular tissue is most 

 abundant and soft After descending awhile in tliis manner, 

 they turn outwards and interlace themselves with those which 

 were previously formed." 



Oryptogamons or Flowerless Planta. 



