EXPLANATION OF THE ILLUSTRATION 
Prare XXII. (Upper) Ponreperta corpata L. 
Habit photograph of Pontederia cordata in the 
headwaters of the Rio Pacoa, Comisaria del 
Vaupés, Colombia. 
(Lower) Lerrarsia corompiana R. EF. Schultes. 
Habit photograph of Leitgebia colombiana (the 
shrub with the fine leaves) at Yapobodd, Rio Ku- 
duyari, Comisaria del Vaupés, Colombia. 
Photographs by Ricuarp Evans Scuuttes 
