62 A. H. Graves, 



PAGES 



1. The Leaf Blade 89 



a. Epidermis 90 



(1) Chloroplasts . 90 



(2) Marginal Teeth 90 



(3) Secretion Cells 90 



(4) Absence of Stomata 91 



b. Subepidermal Layer 91 



c. Vascular System ........ 91 



(1) Course of Vascular Bundles 



(2) Structure of Vascular Bundles 



d. Lacunae ..... 



e. Comparison with Other Potamogetonaceae 



2. The Stipular Sheaths . 



a. Structure . . . . 



b. Development .... 



c. Function ..... 



d. Morphological and Morphogenetic Considerations 

 ^3. Axillary Scales .... 



a. General Characters and Anatomj'- 



b. Function ..... 



D. Subfloral Leaves .... 



E. Scale Leaves 



1. The Vegetative Scale Leaf . 



a. General Characters . 



b. Internal Structure 



2. The Floral Scale Leaf . 

 a. General Characters and Structure 

 Orientation of Scale Leaves in Floral Begion 

 Summary of Distinguishing Characters 

 Morphological and Physiological Natm-e of Scale Leaves 



Comparison with Other Potamog 

 Boot 



A. General Characters 



B. Boot Arrangement 

 Anatomical Structure 



C. 



etonaceae 



The Coleorrhiza 



The Growing Point of the Boot 

 The Anatomy of the Mature Boot 

 a. Epidermal Begion 



(1) The Boot Hairs 



Cortex ..... 



Endodermis .... 



Vascular System 



Brief Comparative Study of Boots of Other 

 getonaceae 

 D. Functions of tlie Boot. 



b. 

 c. 

 d. 

 e. 



Potamo 



