PONDWEED FAMILY 101 
PLATE 5 
1. Potamogeton Oakesianus. 2. P. pectinatus. 3. Zannichellia palustris. 
4, Potamogeton crispus. 5. Naias gracillima. 6. Ruppia maritima. 7. Pota- 
mogeton filiformis. 8. P. dimorphus. 9. P. zosteraefolius. 10. Naias 
marina. 
