CHAPTER I 

 SEEDS AND SHOOTS 



THE earth is clothed with plants. All these plants are the 

 results of propagation. 



Plants perpetuate themselves and increase their numbers 

 by many means. These means are sexual (by seeds and some 

 kinds of spores), and asexual (by vegetative parts). 



Seeds are the results of the fertilization of the ovule (strictly 

 of the egg-nucleus of the ovule) by the germ-nucleus of the 

 pollen-grain. The ovule, with its integuments and perhaps 

 with adhering parts, ripens into the seed. Of many forms, sizes 

 and colors are the seeds of plants. So various are they that 

 we visualize no seed-form, as we visualize heart-form or rose- 

 form, and many of them are hardly recognizable. Yet they all 

 have this in common, that they contain a dormant or quiescent 

 embryo. This embryo is a rudimentary or minute plant. 

 When the conditions are right for the plantlet to resume its 

 growth, we say that the seed germinates. 



Not only does the seed reproduce the parent, but it disperses 

 the species. In fact, the word disseminate means to sow or 

 scatter seeds, although we now disseminate knowledge as well 

 as seeds. The act of falling from the receptacle places the seed 

 in a different position from that of its parent stock. Often 

 the seed is carried by wind, being whirled by means of wings, 

 as in maple and ash ; floated by means of down or plumes, as 

 in thistle, dandelion and poplar; driven on the snow and ice 

 from stalks that stand stiff in the winter. It may be carried 

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