36 
PLANT MORPHOLOGY. 
EXAMINATION OF CELL-CONTENTS. 
I. Definite Form. 
II. Without 
Definite Form. 
A. Crystalline. 
B. Crystalloids. 
C. Non-crystalline. 
1. Calcium oxalate 
4. Inulin 
6. Starch 
11. Protoplasm 
2. Sugars 
5. Protein crystal- 
loids 
7. Plastids 
% [8. Oil 
% 1 
12. Inulin. 
3. Alkaloids 
(Either separate 
13. Mucilage 
or in aleurone 
grains.) 
o i 9. Tannin. 
'So 
14. Tannin 
p 10. Mucilage. 
15. Resin 
1. See page 25. 2. Crystalline in fresh material treated with alcohol; the 
glucoses give a reddish precipitate with Trommer’s Reagent, consisting of solu- 
tions of copper sulphate (concentrated) and potassium hydrate (50 per cent.). 
3. In specimens treated with acids, alkalies or alkaloidal reagents. 4. Sphere- 
crystalloids In fresh material treated with alcohol. 5. See page 30. 6. Gener- 
ally colored blue with iodine solutions. 7. See page 11. 8. The essential oils are 
more soluble in alcohol and this distinguishes them from the fixed oils. 9. Gives 
bluish or blackish precipitate with solutions of ferric acetate, or a brownish pre- 
cipitate with solutions of copper acetate. 10. Colored blue with solutions of 
methylene blue in alcohol or in glj cerin. 11. Finely granular and colored yel- 
lowish or yellowish brown with solutions of iodine or chlor-zinc-iodide. 12. In 
irregular masses in dried specimens. 13. See No. 10 14. In dried specimens 
tannin is sometimes associated with other substances as mucilages and resins, 
forming irregular masses, but it is usually absorbed by the cell wall. 15. Usually 
in yellowish or reddish masses, colored greenish with copper acetate solution, 
or reddish with tincture of alkanet. 
D. THE CELL WALL. 
I. ORIGIN AND COMPOSITION OF WALLS. 
The cell wall is formed by the protoplasm, and by 
some authors is looked upon as a differentiated por- 
tion of the outer layer of the protoplasm, the latter 
ying close to the wall in a normal turgescent cell. The 
composition of the wall varies at different stages of the 
rowtli of the cell, and according to the various func- 
tions it has to perform. 
In order to thoroughly understand the nature and 
composition of the cell wall, it is necessary to study the 
origin and formation of new cells. Growth of the plant 
is attended not only by an increase in the size of the 
