The Morphology of Ruppia Maritima. 63 
PAGES 
ECOLOGY OF THE VEGETATIVE ORGANS 115 
INTRODUCTORY ; 115 
Hypropuytic ADAPTATIONS 116 
A. The Shoot 116 
1. Gross Meratelepical Mteptcpole 116 
2. Internal Structural Adaptations 117 
a. Epidermal Modifications 117 
b. Development of Air Spaces 118 
c. Absence of Mechanical Tissue 119 
d. Reduction of the Vascular aes 119 
B. The Root 120 
1. Gross Madgaoloeical Misatatione, 120 
2. Internal Structural Adaptations 121 
a, Air Spaces 121 
b. Reduction of the Geecular Sy stem 121 
Hatopuytic ADAPTATIONS 121 
A. General | 121 
B. The Adaptation to a ‘Salt Water Bnaerommnent 122 
ADAPTATION AND HEREDITY 126 
SUMMARY 126 
REPRODUCTIVE ORGANS 128 
MorpHoLocy oF THE FLOWER 128 
FrioraLt DryELOPMENT 130 
MicrosPoRANGIUM 131 
MEGASPORANGIUM 135 
FrmMaLe GAMETOPHYTE 136 
Mae GAMETOPHYTE 139 
POLLINATION . 143 
FERTILIZATION 144 
ENDOSPERM 145 
EMBRYO : 146 
FRUIT AND SEED 156 
SEEDLING 158 
SUMMARY OF PARIS ON R E PRODUCTIVE ORGANS, EM. 
BRYO, &ec. 160 
SUMMARY OF RELATIONSHIPS TC O OTHER PO TAMOGETON- 
ACEAE 162 
BIBLIOGRAPHY . 165 
EXPLANATION OF PL ATES 
170 
