14 



ESSENTIALS OF BOTANY 



Sketcli an unsoaked kernel so as to show the grooved side where 

 the germ lies. Observe how this groove has become partially filled 

 up in the soaked kernels. 



Remove the thin, tough skin from one of the latter and notice its 

 transparency. This skin — the bran of unsifted corn meal' — does 

 not exactly correspon'l to the testa and inner coat of ordinary seeds, 



since the kernel of corn, like all other 

 grains (and like the seed of the four- 

 o'clock), represents not merely the seed, 

 but also the seed-vessel in which it was 

 formed and grew, and is therefore a 

 fruit. 



Cut sections of the soaked kernels, 

 some transverse, some lengthwise and 

 parallel to the flat surfaces, some length- 

 wise and at right angles to the flat sur- 

 faces. Try the effect of staining some 

 of these sections with iodine solution. 



Make a sketch of one section of each 

 of the three kinds, and label the dirty 

 white portion of cheesy consistency, 

 embryo ; and the yellow portions and 

 those which are white and floury, endo- 

 sperm. 



Chip off the endosperm from one 

 kernel so as to remove the embryo free 

 from other parts. ^ Notice its form, 

 somewhat triangular in outline, sometimes nearly the shape of a 

 beechnut, in other specimens nearly like an almond. 



Estimate what proportion of the entire bulk of the soaked kernel 

 is embryo. 



Split the embryo lengthwise so as to show the slender, somewhat 

 conical plumule.'^ 



1 The embryo may tie removed with great ease from kernels of rather 

 mature green nn-n. Boil the corn for about twenty miuutes on the cob, then 

 pick the kernels off one by one with the point of a knife. They may be 

 preserved indefinitely in alcohol of 50% or 75%. 



2 The teafhur may well consult Figs. 56-6-1, inclusive, in Gray's Structural 

 Botany. 



I'iG. 6. Lengthwise Section 

 of Grain of Corn. (Magni- 

 fied about three times.) 



y, yellow, oily part of endo- 

 sperm; JO, white, starchy part 

 of endosperm ; j), j)lumule ; 

 s, the shield (cotyledon), in 

 contact with the endosperm 

 for absorption of food from 

 it ; /■, the primary root. 



