A GUIDE AND KEY TO AQUATIC PLANTS 55 



40. Leaves entire or nearly SO-.:. 65, 



40. Leaves prominently toothed 77. 



41. Leaf, when examined against light with lens, show- Hypericum, p. 123. 

 ing semitransparent dots; flowers yellow or pink 



(fig. 37). 



41. Leaves not showing semitransparent dots 42. 



42. Leaves broadened at base 43. 



42. Leaves narrowed to base 46. 



43, Leaves mostly under 2.5 cm. long 44. 



43. Leaves mostly over 2.5 cm. long 45. 



44. Plant aromatic when crushed (fig. 38) Hydrotrida, p. 135. 



44. Plant not aromatic when crushed (fig. 39) Herpestris, p. 135. 



FlQURE 37. 



Figure 38. 



Figure 39. 



