dorsal 

 grooves 



central 

 ridge 



D 



Figure 1. 

 Alisma gramineum: \. habit of emersed plant, x '/i. B. 

 habit of submersed plant, x '/i. C. fruiting head, x 4. D. 

 achene, side view, x 8. E. achene, end view, x 8. 



