Fig. 416: Polygonum hydropiperoides var. hydropiperoides: a, perianth, spread 

 open, showing irregular stamen insertion, x 6; b, pistil, x 6; c, mature achene, x 8; 

 d, mature achene (cross section), x 8; e, upper part of spike, showing the ciliate 

 sheathing bract subtending the flowers, x 4; f, stipular leaf sheaths, coarsely strigose, 

 ciliate at apex, x 1%; g, habit, showing roots at lower nodes and slender interrupted 

 spikes, X %. (From Mason, Fig. 202). 



