LABORATORY PRACTICE 



through both micropyle and hilum. Examine the cut sur- 

 faces with the lens and notice : 



1. The seed-coats. 



2. The white, translucent endosperm. 



3. The coiled embryo, lying within the endosperm. 



4. Removing the embryo, examine it with the lens and 



notice that there are no distinct parts. The end 

 towards the micropyle is the caulicle, the other is the 

 single cotyledon. 



5. Make sketches showing these points. 



XV. Take a seed of the Pinon Pine and notice : 



1. Its size, shape, color, etc. 



2. The micropyle at the narrower end. 



3. Remove the thick shell, which in the Pine Seed repre- 



sents the single seed-coat characteristic of this group 

 of seeds and notice : 



4. The kernel. 



XVI. Cut a longitudinal slit in the side of the kernel, and 

 carefully split (by the aid of your thumb-nails) the kernel 

 into two halves, thus exposing : 



1. The embryo in the centre surrounded by the firm white 



endosperm. 



2. Study and sketch the embryo, noticing : 



3. The caulicle, straight and undivided, and 



4. The several (6-n) narrow cotyledons. 



XVII. Take the kernel of another seed and make a cross- 

 section through the region of the cotyledons. Examine 

 with the lens and make a sketch, noting : 



1 . The ring of endosperm, enclosing 



2. The cotyledons, arranged in a circle or whorl. 



