EXERCISE 26 

 A STUDY OF THE RYE HEAD 



Object. To examine the head of rye and become 

 familiar with the shape and arrangement of its different 

 parts. 



Explanation. The head of rye is commonly called a spike. 

 It is made up of several parts, of which the grain is the most 

 important. The head is composed of a single rachis and 

 several spikelets. The spikelets are attached to both sides 

 of the rachis. There are two divisions of the spikelet, each 

 division containing one kernel. There is an outer glume, 

 a flowering glume, and a palea for each kernel. The kernel is 

 inclosed by the flowering glume on the outside and the palea 

 on the inside. The flowering glume does not entirely inclose 

 the kernel, and a small portion of it is exposed. The outer 

 glume is small and does not inclose the flowering glume. The 

 rye kernel is similar to the kernel of wheat, though it is some- 

 what more slender, more pointed at the germ end, and the 

 crease is not so deep. There are only two flowers in a spike- 

 let, and both of them develop. 



Equipment. Heads of rye sufficient to supply all the 

 members of the class. 



Directions. Make two drawings of the entire head of rye. 

 Make a drawing showing the side view, then turn the head 



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