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PUBLIC HEALTH BULLETIN NO. 286 



15. Leaves coming off of a creeping or horizontal stem Hydrocotyle, p. 130. 

 (fig. 12). 



15. Leaves scattered along an upright stem 16. 



16. Leaves opposite 17. 



16. Leaves alternate or irregularly borne 18. 



17. Stems 4-angled; flowers small, in dense clusters in the Lycopus, p. 135. 



axils of the leaves (fig. 13). 



17. Stem round, or nearly so, in cross-section; flowers Bidens, p. 140. 



showy, yellow (fig. 14). 



x'/2 

 Figure 12. 



^U 



Figure 13. 



Figure 14. 



18. Leaves with veins radiating out from base 19. 



of leaf. 

 18. Leaves with central mid-vein and smaller Rorippa, p. 119. 

 veins branching from this (fig. 15). 

 19. Base of petiole expanded; plants under 4 dm. tall (fig. Ranunculus, p. 118. 



16). 

 19. Base of petiole not expanded; plants large, 5 dm. tall Hibiscus, p. 122. 

 or taller (fig. 17). 



FiGUBE 15, 



Figure 16. 



Figure 17. 



