298 
PHARMACEUTICAL BOTANY 
Flowers trimerous (having the parts of each whorl in threes or 
multiple thereof). 
Secondary growth in roots generally absent. 
Medullary rays generally absent. 
Fig. 164. —Pistillate and staminate inflorescences of corn (Zea mays). 
(Robbins.) 
I. Order Graminales.— Graminece or Grass Family .—Mostly 
herbs with cylindric, hollow jointed stems whose nodes are swollen. 
The leaves are alternate, with long split sheaths and a ligule. Flow- 
