462 PHARMACEUTICAL BOTANY 
suspensor attached to the anlage of the embryo which has been 
pushed through the basal membrane of the egg deep into the pro- 
thallus by the elongating cells of the suspensor. The embryo 
lives as a parasite on the tissue of the female gametophyte. After 
differentiation has proceeded in the body of the embryo to a 
certain point, z.e. where two cotyledons or seed leaves and a central 
axis consisting of a hypocotyl (part below the attachment of the 
cotyledons) and an epicotyl (part above the cotyledons) have been 
formed, growth of the embryo becomes suspended. 
Nourishment is stored in the cells of the prothallus around the 
embryo forming the endosperm. The integument undergoes 
changes in its cells to form a firm seed coat consisting of a strong 
and a fleshy layer surrounding the nucellus. The micropyle 
persists as a tubular opening in the seed coat. 
GERMINATION OF THE SEED.—The mature seeds drop from the 
megasporophyll of the mature cone to the ground and some of 
them germinate. In this process the seed absorbs water. ‘The 
enzymes within its cells change the reserve or stored food within 
the endosperm into water soluble substances which are converted 
into new substances or protoplasm, as a result of which the 
Out ine or Lire Hisrory or ZAMIA 
Zygote | Zygote 
Embryo Embryo 
Mature male sporophyte Mature female sporophyte 
Microsporophyll Megasporophyli 
Microsporangium Megasporangium 
Microspore mother cell Megaspore mother cell 
Microspore Megaspore 
Male gametophyte Female gametophyte 
Antherozoids 
-_—~ Fertilization 
| 
a 
Zygotes (destined to develop into male and 
female sporophytes) 
