PLATE XVIII. 



Figs. 1-4. — HaUcornaria plumosa. 

 Fig. 1. — Natural size. 



Fig. 2. — Portion of stem witli hydroclaJia ; luaguified. 

 Fig. 3. — Portion of hydrocladium, still further magnified ; lateral view. 

 Fig. 4. — Same ; front view. 



