122 BOTANY. 



Observe whether the cotyledons in all cases rise into the 

 light and air. Observe whether all cotyledons are shaped 

 alike, and also whether they resemble the true leaves of 

 the plant.* 



EXERCISE LVI. 

 Position of the Embryo in Seeds. 



You are now familiar with the different aspects of the 

 embryo in many different seeds. You have seen it large 

 and small, straight and curved, outside the albumen and 

 imbedded within it ; sometimes with flat cotyledons, and 

 sometimes with cotyledons folded or coiled in various 

 ways and degrees. We are now to observe its relation to 

 the parts of the seed. 



In studying ovules, you found the hilum and the micro- 

 pyle, and you may find the same parts in the seeds that 

 were once ovules. The hilum of seeds is usually obvious 

 enough, and the micropyle may be easily found. You have 

 only to soak the seed till its coats are distended with 

 water, and, on squeezing, the micropyle is made apparent 

 by the escape of water at that point. The place of the 

 micropyle is important, because the radicle of the embryo 

 always points toward it, and, in sprouting, issues through 

 it, and the relation of the micropyle to the hilum deter- 

 mines the attitude of the embryo. Seeds are straight, half 

 inverted, inverted, and curved, the same as ovules, and 



* A word of caution may not here be amiss. There is danger that 

 the sympathy of teachers with bright and interested pupils will lead 

 them to tell in advance what children can find out for themselves by 

 continued observation. The relation between number of cotyledons 

 and venation is an instance of such temptation. By-and-by, when the 

 leaves of his growing plants are well developed, the pupil might be put 

 in the way of discovery, by asking him to make a list of his monoco- 

 tyledons, and to give their venation in each case. Let him do the 

 same with his dicotyledons. He will now see a perfect uniformity of 

 relation in a few cases, and will be curious to know if it is everywhere 

 constant. He will thus arrive at the induction by his own observation. 



