lution, and acquaintance with the conditions which control their 
synthesis and gradual formation in the plant can only be had by 
patient research. The simpler compounds of which any com- 
_ plex substance is built, if located as ¢ompounds of lower plants, 
would indicate the lines of progression from the lower to the 
higher groups, : 
- Ithas been already said that every plant contains compounds 
peculiar to it, but certain compounds seem to play a special part 
in plant evolution, since the wax and tannin of the vascular 
‘typtogams lead to the tannin and wax groups of the apetalous 
Plants, and the starch of these lower plants to the great starch 
groups of the monocotyledonous. It will not be out of place 
to note here that the greatest accumulations of starch occur 
‘m plant orders just before they pass on to a higher plane of 
Solution, This is seen, for example, in the palm and neigh- 
boring orders of the first plane, and among the Lirioideæ of the 
nd plane, since these plants are the richest in starch con- 
‘nts, and it seems as if they were preparing by large reserves 
/ food-supply for their higher position, represented by more 
ved groups, where the demands for nutrition are greater. 
the line of cane-sugar indicates that sugar occurs promi- 
in plants passing from simplicity to multiplicity of floral 
s, and the glucosides in their turn are found in the middle 
so plant development, assisting the plants to the highest 
> of cephalization. F 
22 XXVIL isa chemical representation, drawn after Heckel’s 
ucal table, and from what has preceded it will be easily 
‘hended. It is not to be inferred that all classes of chemi- 
compounds found in plants are represented, since only a few 
been used for illustration, nor that all of these given com- 
S only occur in the designated plant groups, since they 
Por in traces or varying quantities elsewhere. However, 
Compounds are conspicuous as being especially typical of 
Ma Sroups which correspond to their location, and where 
“Sence is doubtless associated with the plants’ evolution. 
chemical compounds which may be said to be typical of 
‘ht of «: Species, or an individual member of a series would be 
— in this general presentation. : 
dead Plant groups, as the Proteacez, orchids, and Composite, 
= © 1n esthetic beauty at the expense of their chemical con- 
= 
