CHAPTER VIII 

 THE PARTS OF A SEED-PLANT 



91. Flax as a type. Dc Candolle, one of the most learned 

 of French l)otanists, was wont to say that he could teach 

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

 had in mind was douljtless 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 

 u]ion which all ]ilants are built. His handful of specimeiis 

 would have been so chosen that (>ach might exhibit especially 

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

 once as a convenient standard of con.iparison and as a means 

 of teaching truths of very wide application. A form wliich 

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

 ists call a tiipi'. 



Flax (Figs. 217 I, 11) will serve well as our t>-pe of phen- 

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

 they commonly show, and exhibits them in comparatively 

 unmotlified condition, like all true flowering plants it prt)- 

 duces seeds. 



92. The seed may he compar(Hl roughly to an egg. Much 

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

 mass of food material proA-ided for the chick or germ which 

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

 seed-coat (c) enclosing .srcil-food (f) and a germ or r(;(/)r//() ' (e). 

 Much of the food provided for the flax embryo is already 

 stored within the little jilant 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 < Or. iinliri/nn, ^ci'iii. 

 - Al-lm'mcn -■; I., nlhus. while. 



31G 



