200 
PHARMACEUTICAL BOTANY 
Plants pollinated through the agency of water currents are known as 
Hydrophilous. To this class belong such plants as live under water 
and which produce flowers at or near the surface of the same. Exam¬ 
ple: Sparganium. 
Animal-pollinated plants are called Zodphilous. Some plants like 
the Nasturtium and Honeysuckle are pollinated by humming birds. 
Before the pollen grain has been deposited upon the stigma and 
during its germination thereon, a series of events affecting both the 
pollen grain and the embryo sac occur which result in the ultimate 
formation of the male and female gametophytes. 
Maturation of the Pollen Grain and Formation of the Male 
Gametophyte. —The substance of the microspore (pollen grain) 
divides into two cells, the mother and tube cells of the future male 
gametophyte. The nucleus of the mother-cell divides to form two 
sperm nuclei. Within the tube cell is found a tube nucleus em¬ 
bedded in protoplasm. Upon germinating the partition disappears 
and the thin endospore, carrying within it the protoplasm in which 
are embedded the tube nucleus and two sperm nuclei, penetrates 
through a deficiency of the exospore. The contents of the pollen 
grain at this stage is called the male gametophyte. 
Maturation of the Embryo Sac and Formation of the Female 
Gametophyte. —The nucleus of the megaspore or embryo sac under¬ 
goes division until eight daughter-nuclei are produced which are 
separated into the following groups: 
(a) Three of these nuclei occupy a position at the apex, the lower 
nucleus of the group being the egg or ovum, the other two nuclei 
being the synergids or assisting nuclei. 
( b ) At the opposite end of the sac are three nuclei known as the 
antipodals which apparently have no special function. 
( c ) The two remaining nuclei {polar nuclei) form a group lying 
near the center of the embryo sac which unite to form a single 
endosperm nucleus from which, after fertilization, the endosperm or 
nourishing material is derived. This stage of the embryo sac con¬ 
stitutes the female gametophyte. 
Fertilization in Angiosperms. —After the pollen grain reaches the 
stigma, the viscid moisture of the stigma excites the outgrowth of the 
male gametophyte which bursts through the coats of the pollen 
