CHAPTER VIII 

 THE PARTS OF A SEED-PLANT 



91. Flax as a type. De CandoUe, one of the most learned 

 of French botanists, was wont to say that he could teach 

 all he knew of botany from a handful of plants. What he 

 had in mind was doubtless the great truth that among the 

 resemblances of plants to one another there are some of such 

 fundamental importance that it becomes possible to discern 

 amid the endless variety of forms a few plans of structure 

 upon which all plants are built. His handful of specimens 

 would have been so chosen that each might exhibit esjiecially 

 well the features common to many kinds, and thus serve at 

 once as a convenient standard of comparison and as a means 

 of teaching truths of very wide application. A form which 

 in this way is representative or typical of any group, natural- 

 ists call a type. 



Flax (Figs. 217 I, H) will serve well as our type of phen- 

 ogams or seed-plants because it possesses all the parts which 

 they commonly show, and exhibits them in comparatively 

 unmodified condition. Like all true flowering plants it pro- 

 duces seeds. 



92. The seed may be compared roughly to an egg. Much 

 as in a hen's egg, for example, we have the shell covering a 

 mass of food material provided for the chick or germ which 

 lies within it, so in the seed (Fig. 279A) we find a protective 

 seed-coat (c) enclosing seed-food (f) and a germ or embryo ^ (e). 

 Much of the food provided for the flax embryo is already 

 stored within the little plant itself; what remains to be ab- 

 sorbed has been likened to the white of egg and is called the 

 albumen ^ of the seed. The embryo within the seed is found 



' Em'bry-o < Gr. embryon, germ. 

 ^ Al-bu'mcn < L. alhus, white. 



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