THE SEED'S FOOD-SUPPLY 137 



sequently it is only necessary to glance at the foliage 

 in order to know whether the seed has two cotyledons 

 or only one. I will say further that pines, firs, and 

 the other resinous trees have as many as ten cotyle- 

 dons, which show themselves as a delicate tuft of 

 leaves when the little plant comes out of the ground." 



Uncle Paul then led the children into the garden 

 to fix in their minds by observation the lesson they 

 had just learned. "Gather haphazard," said he, 

 "the first leaves you come to; then examine them and 

 tell me how many cotyledons the seed must contain. 

 First, here is the iris, with large blue flowers and 

 sword-shaped leaves. ' ' 



"I see," said Jules, "veins running in regular 

 lines side by side, without ever joining one another. 

 Since these veins are parallel the iris seed has only 

 one cotyledon." 



"And this blade of grass, this also that I pick from 

 a corn-stalk?" asked his uncle. 



' ' They, too, have parallel veins, both of them ; and 

 so their seeds must have only one cotyledon." 



"And this grape-leaf, this leaf of the cherry tree?" 



"It's my turn now," Emile hastened to interpose. 

 "The veins form a sort of lace with very fine meshes. 

 The grape and the cherry have two cotyledons." 



"It is as easy as that, my friends. The leaf with 

 its arrangement of veins shows us the fundamental 

 characteristics of the plant. It tells us whether the 

 germ is fed by one nursing-leaf or two, whether the 

 young plant comes up with one seminal leaf or two." 



