62 A. H. Graves, 
PAGES 
1. The Leaf Blade 89 
a. Epidermis . 90 
(1) Chloroplasts oi PU 
(2) Marginal Teeth . . 90 
(3) Secretion Cells . 90 
(4) Absence of Stomata . 91 
b. Subepidermal Layer Jl 
c. Vascular System 91 
(1) Course of Vascular Bandies 91 
(2) Structure of Vascular Bundles 92 
d. Lacunae 92 
e. Comparison with Other Ta amague avs eere 92 
2. The Stipular Sheaths 93 
a. Structure 93 
b. Development 93 
ce. Function Os 
d. Morphological and atonphowencire Considerumane 95 
3. Axillary Scales 96 
a. General Characters and vatocaee 96 
b. Function 97 
D. Subfloral Leaves 97 
KE. Scale Leaves 98 
1. The Vegetative Sc ale Teese 99 
a. General Characters Si 
b. Internal Structure op abe 
2. The Floral Scale Leaf . : si 
a. General Characters and Structure . : 99 
3. Orientation of Scale Leaves in Floral Region . 100 
4. Summary of Distinguishing Characters : 101 
5. Morphological and Physiological Nature of Scale hee 102 
6. Comparison with Other Potamogetonaceae 102 
Roor 102 
A. General Ghani’ 102 
B. Root Arrangement 103 
C. Anatomical Structure 104 
1. The Coleorrhiza 104 
2. The Growing Point of the Bnet 108 
3. The Anatomy of the Mature Root 109 
a. Epidermal Region 109 
(1) The Root Hairs 110 
b. Cortex 111 
c. Endodermis bl 
d. Vascular System 112 
e. Brief Comparative Study of ages of Other Potames 
getonaceae : : $ 112 
D. Functions of the Root. 
113 
EE 
a 
