- _ crystalline form, 
Has present in 
726 Comparative Chemistry of Higher and Lower Plants, [Aug 
starch of the cryptogams will be found gelatinous in Alge, 
replaced in Fungi as glycogen, and only in the lowest of the 
flowering plants does it occur in the simplest stratified form; 
from this stage to the highest of plants, the Composite, in which — 
it occurs as a crystalline substance called inulin, it may be 
from plane to plane of plant-group development in a succession | 
of stratification until it reaches its highest point in our most 
evolved plants. So strongly marked-are these varieties of starch- 
forms that some investigators, notably Nägeli, have proposed 
this means for the identification of many plant families. 
The many kinds of vegetable sugars known to chemists also 
have their locations, not only during different stages of the indi- 
vidual plant-growth and in different parts of the plant, as synat- | 
throse,* the especial sugar of the unripe grain of rye and wheat 
but also in certain families, some one kind of sugar will prè 
dominate in many of the individuals. The tannins of the oak, 
beech, and poplar are not those of the higher plants. 
t a certain stage of plant evolution, glucosides, substances 
capable of splitting up and yielding, among other products, 
sugar, appear. I have observed in those plants where large pê% | 
centages of such substances are found a diminished re 
of starch and sugar,? or their absence, notably in soap-bark am 
species of the Yucca. 
` The waxes, oils, camphors, resins, acids, and other a : 
Seontable compounds might be similarly cited as offering chat 
acteristic properties in various plants in which they appea! but 
the examples given are ample to illustrate my point, that | 
chemical compounds of plants should be considered from ne 
sides, viz.: 
I. In their own development through many plant group al 
from a gelatinous or undifferentiated compound to a po lymet, q 
a substance of the same chemical formula having a $0 
2. In their succession of changes which may be observei 
* Ri Of Senda, bp A, Muni Ana. A 4003 Jove : 
Soe F Feb. pag 4 173. F untz, Ann, Agronom., xii. 399 ! 
Eigse 
- Soc., Yucca angustifolia, 
+ 
