NOTES ON SOME CURIOSITIES OF ORCHID BREEDING. 449 



owing, no doubt, to the fact that the ovules of Orchids being so 

 minute, the further processes would be extremely difficult to 

 follow. Yet there can be little doubt that the further details of 

 fertilisation in Orchids (in common with those already observed) 

 are much the same as in other flowering plants. Indeed, the 

 ultimate processes of fertilisation seem to be much the same in 

 all forms of life. Professor Strasburger and others have worked 

 out the details of fertilisation with marvellous precision in a 

 plant of the genus Ornithogalum (Star of Bethlehem), which 

 belongs to the Liliacese order, a family closely allied to Orchids. 

 Professor Strasburger observed (Kerner and Oliver, " Natural 

 History of Plants," ii. p. 416) that the pollen grain contained one 

 or two germ cells, which were made up of a nucleus surrounded 

 by a small portion of naked protoplasm. One of these germ cells, 

 or pollen cell, as we may conveniently call it, is carried along 

 near the tip of the pollen tube as it gradually lengthens, and 

 eventually is discharged from the tube through the opening of 

 the ovule into the embryo-sac. Having reached this, the pollen 

 cell at once makes for the egg cell contained therein, and, being 

 many times smaller than the egg cell, enters into it, the nucleus 

 of the pollen cell uniting with the nucleus of the egg cell, the 

 outcome being a fertilised egg cell which in due time becomes 

 the living embryo of the seed. In this way, by the union of the 

 pollen cell of the father with the egg cell of the mother, a new 

 individual is brought into being. We have already seen that 

 characters are handed on equally by both parents ; therefore it 

 necessarily follows that in some way or other the determinants 

 of the characters of the father parent are packed up in the small 

 compass of the pollen cell, and those of the mother parent in 

 the egg cell. 



We have seen that the pollen cell is many times smaller 

 than the egg cell, consisting as it does almost wholly of nucleus, 

 and we also know that the nuclei of both are fairly balanced in 

 size and contain the same elements. Therefore it naturally 

 follows that in the handing down of characters from one genera- 

 tion to another, the nucleus is the all-important matter, and the 

 surrounding protoplasm, which is so considerable in the egg cell, 

 and so inconsiderable in the pollen-cell, has little or nothing to 

 do with it, though no doubt it serves a useful purpose as a source 

 of food supply for the nuclei and the future embryo. 



