282 STRUCTURAL BOTANY 



ground The cotyledons during germination absorb the 

 remainder of the endosperm. The apex of the stem 

 directs itself upwards ; the seed-coat is at first lifted 

 up upon the cotyledons, but is soon cast off as they 

 expand (Fig. 116). The cotyledons become green, and 

 the young plant is now able to assimilate its own food. 



SUMMARY 



We will now pass rapidly in review those facts in 

 the reproduction and development of the Fir which 

 are typical of gymnospermous plants generally, and 

 which indicate their relations, on the one hand to the 

 Angiosperms, -and on the other hand to the Flowerless 

 plants. 



Apart from the peculiarities in the general 

 morphology of the male flower, which have been 

 sufficiently dealt with already, we find a characteristic 

 feature in the considerable number of cells which are 

 formed within each pollen-grain. This, as we shall 

 see later on, is a very significant fact. The produc- 

 tion of all these intermediate cells, before the actual 

 generative cells are set apart, is really a cryptogamic 

 character, and is one indication, among many, that 

 the Gymnosperms are on a different level from all 

 other Flowering plants. 



The gymnospermy, or direct pollination of the ovule 

 without the intervention of a stigma and style, is 

 itself a point of great importance. Fertilisation by 

 means of a pollen-tube is one of the chief characters 

 of Phanerogams. In Gymnosperms we still have tho 

 pollen-tube, but its work is more limited than in 



