Fig. 6. The growth of the pollen-tube and the union of the maternal and the 
paternal cells, which are responsible for the new generation. (I) Section of a 
lily pistil, showing the course of the pollen tubes. ( After Kerner and Oliver.) 
(II) Section of the pistil of a cotton flower, showing the pollen tube ( P) just 
entering the ovule. (E) The plant egg. (After Duggar.) (II I ) Upper portion 
of a section of the ovule or egg-containing organ of the lily. Union of the 
sperm or male cell (c) and the egg (b)isin process of taking place. (A) is 
the remnant of the pollen tube, and (D) is the second sperm which unites with 
the two endosperm cells close to it, to form the starchy food substance of the 
seed. (After Blackman.) 
