Fig. 408: Polygonum amphibium: a, achene (cross section), x 6; b, mature achene, 

 X 6; c, flower, showing exserted stamens, x 6; d, perianth, spread open, showing the 

 prominent glandular disk and the regularly inserted stout filaments, x 6; e, terrestrial 

 plant, showing habit, scabrous pubescence, x %; f, stipular sheath of terrestrial plant, 

 scabrous, the broad margin ciliate. x 3, g, stipular sheath of aquatic plant, glabrous 

 and membranous, x 2; h, habit of aquatic plant, showing the rooting nodes, the 

 glabrous floating leaves and the short dense flowering spikes, x %; i, lower part of 

 spike, showing the bilobed sheathing bracts and the flowers on short glabrous pedicels, 

 x 4. (From Mason, Fig. 199). 



