PARTS OF SEEDS: CORN SEEDLINGS 



Fig. 16. 

 Grain of corn 

 showing groove. 



on the outer end as in the " flint" corn, or with an indentation 

 as in the ''dent" com, and often with a sharp, somewhat spinous 

 process. The grains of sweet corn are very much wrinkled. 

 Upon one side near the smaller end there is a 

 shallow groove underneath the surface of which 

 the embryo lies. 



17. The embryo in the grain of corn. A 

 section length- wise through the middle of a grain 

 of corn, which has been soaked in water, shows 

 the parts of the embryo, and the position which it 

 occupies in the kernel (fig. 17). The embryo lies 

 next the groove just underneath the thin fruit 

 coat.* The root end lies next the small end of the grain. 



It is quite easy to see that the most prominent part of the root 

 at this stage is the root sheath. Within the root sheath lies the 

 primary root or radicle of the embryo, like 

 a finger lying within a glove finger. At the 

 opposite end of the embryo lies the narrow 

 conical fold of a leaf, and sometimes several 

 leaves in section can be seen lying one 

 within another, or sections of the inner 

 folds of the outer leaf. This cluster of 

 young leaves is the plumule. The stem is, 

 in this stage, shorter than the root or leaf 

 and is a very short piece of the embryo 

 lying between the other two parts. Upon 

 the opposite side of these parts of the 

 embryo from the groove in the grain is 

 another part of the embryo, which lies 

 somewhat obliquely in the grain. It is 

 attached near the center of one side to 

 the stem or caulicle and this point of connection can be seen 

 quite clearly. iTiis is the scutellum of the embryo, so called 

 because of its form and the central attachment at one side which 

 * In the grain of corn, wheat, etc., the fruit coat consists of the pericarp 

 (wall of ovary). The very thin seed coats lie beneath. 



cot 



Fig. 17. 



Section through grain of 

 corn. /. c. fruit coat; st. 

 starch, the aleurone layer 

 lies between the starch and 

 seed coats; cot. cotyledon 

 {here the scutellum); r. rad- 

 icle Enclosed in root sheath; 

 pl. plumule. 



