XVI 1 1] 



MARE'S-TAIL 



231 



- a.L 



FIG. 151. Hippuris vulgaris, L, A, shoot showing air^ leaves (a.?.), water leaves 

 (w.l.} and roots (r.}. Whorls of flowers at the upper nodes; n lt node with flowers 

 whose anthers have dehisced; n 2 , node with flowers whose anthers are still closed. 

 B, whorl of flowers enlarged, leaves (I) cut away. C, a single flower seen from 

 adaxial side; st = feathery style; an = anther; o = ovary. (Reduced.) [A. A.] 



