696 



THE WONDERS OF GEOLOGY. 



Lect. VII. 



ture peculiar to the dicotyledonous class. In this magnified 

 view of a slice of the common fir {fig. 2), the glands 

 are seen to be arranged in double parallel lines. In a re- 

 markable family of pines, the Araucarice, these bodies are 



Lign. 154. — Illustrations of vegetable structure. 

 Fig. 1. Section of a coniferous tree, showing the concentric and radiated structure. 



2. Longitudinal section of a fragment of pine-wood, magnified to exhibit the 



spotted vessels. 



3. Longitudinal section of two vessels of an Araucaria, magnified to show the 



glands arranged alternately. 



4. A dicotyledonous seed split open ; the germ is seen in the middle. 



5. Section of a monocotyledonous seed, with the germ below. 



6. Dotted tubes of coniferous wood. 



7. Transverse section of a monocotyledonous stem. 



8. Transverse section of a dicotyledonous tree, showing concentric circles, 



medullary rays, and the central pith. 



placed alternately, and sometimes in triple rows. All the 

 trees of this order secrete resin, have branched trunks, and 

 linear, rigid, entire leaves: species are found in the coldest 

 as well as in the hottest regions. The Araucaria la a 



