A GUIDE AND KEY TO AQUATIC PLANTS 



29 



4. Plants bearing linear, sometimes long and 5. 

 ribbon- or thread-like submerged leaves, 

 or compound submerged leaves with nar- 

 row divisions; plants often entirely sub- 

 merged, with or without floating or emersed 

 leaves. 

 4. Plants not bearing submerged linear, ribbon- 26. 

 or thread-like leaves or narrowly segmented 

 submerged leaves; plants often not entirely 

 submerged; submerged leaves, if any, 

 similar to the floating or emersed leaves. 

 5. Submerged leaves bearing bladders; flowers irregular, 



showy yellow or purple (fig. 4) 

 5. Submerged leaves not bladder bearing; flowers regular. 

 6. Submerged leaves compound, made up of 



narrow segments or leaflets. 

 6. Submerged leaves simple, made up of a single 13. 

 narrow blade. 



7. Submerged leaves with a central axis 8. 



7. Submerged leaves irregularly forking 11. 



8. Submerged leaves scattered along almost the 9. 

 entire length of the stem; flower stalks not 

 inflated. 

 8. Submerged leaves gathered along a few centi- 

 meters of the stem; flower stalks inflated 

 (fig. 5). 



Utricularia, p. 137. 



6. 



7. 



Hottonia, p. 132. 



Figure 4. 



Figure 5. 



