16 PHARMACEUTICAL BOTANY 
~~~.the DicotyLepons. The MonocotyLepons [Gk. monos, alone; 
kotyledon, a cup-shaped hollow] are represented by the cat-tails, 
grasses, sedges, lilies, palms, bananas, gingers, orchids, etc. 
They have a single seed-leaf or cotyledon, mostly parallel veined 
leaves and the parts of their flowers are in threes. 
The Dicory.epons [Gk. di, two; kotyledon, a cup-shaped hol- 
low] are represented by such forms as the willows, poplars, 
maples, oaks, chestnuts, geraniums, violets, cherries, roses, beans, 
asters, etc. ‘They have two seed-leaves or cotyledons, netted 
veined leaves, and the parts of their flowers are in fours and fives. 
Every seed plant normally comes from an ovum (egg cell) which 
has been fertilized within the ovule of a flower. The fertilized 
egg or zygote divides and redivides to form at first a nearly uniform 
mass of cells. As these cells continue to multiply a process 
early becomes manifest. This process is called PuystoLOGICAL 
Division or Lapor and consists of the apportioning of separate 
kinds of work to different parts of the same organism. The result 
of the changes occurring in physiological division of labor is called 
DIFFERENTIATION. As the cells continue to increase, unequal 
growth takes place among them and, in time, they become 
differentiated to form a young seed plant or embryo. ‘The 
embryo lies within the ovule which by this time has ripened to 
form with the embryo the structure called the seed. 
Upon reaching suitable soil the seed absorbs water and its 
embryo swells and sprouts forth or germinates, forming a young ; 
seedling plantlet with roots, green foliage leaves and stem. 
Eventually, through further growth and differentiation, a 
mature adult plant is developed which bears flowers in which 
female sexual cells or eggs and male sexual cells or sperms are 
produced. The sperm unites with the egg, fertilizing it, thus. 
starting anew cycle. This process is continued from generation 
to generation. 
