1. 

 1. 



3. 

 3. 



KEY TO GROUPS 



Shrubs or trees Group A, p. 15. 



Vines or herbs 2. 



2. Vines Group B, p. 24. 



2. Herbs 3. 



Plants free-floating Group C, p. 25. 



Plants attached to substratum 4. 



4. Plants floating, submerged, or forming mats on Group D, p. 28. 



or just above the surface of the water. 



4. Plants erect and emergent; rooted to the sub- 5. 

 stratum and extending upward out of the 

 water. 



Plants without leaves or with long narrow leaves at Group E, p. 38. 

 least 12 times as long as broad and usually grass or 

 rush-like. 



Plants with shorter, broader leaves Group F, p. 47. 



KEY TO GROUP A 



1. Leaves very narrow, often needle-like 2. 



1. Leaves with expanded blades 4. 



2. Shrub with yellow flowers (fig. 1) Hypericum, p, 123. 



2, Cone-bearing trees 3. 



3, Needles long and two to several in fascicles (fig. 2) Pinus, p. 68. 



3. Needles shorter, arranged in two ranks along twig, or Taxodium, p. 68. 

 sometimes appressed to twig; not in fascicles (fig. 3). 



Figure 1. 



Figure 2. 



Figure 3. 



15 



