EXERCISE XXIX. 

 THE BARLEY PLANT. 



Supplies (or a Laboratory Section of Twelve. From six to twelve specimens of barley plants showing roots, 

 stems, and leaves; one or two wheat plants; one or two oat plants; twenty-four heads of six-row, bearded, hull- 

 less barley; twenty-four heads of six-row, bearded hulled barley; twenty-four heads of six-row, hooded, naked bar- 

 ley; twenty-four heads of two-row, bearded, hulled barley; twenty-four heads of bearded wheat; twelve two-ounce 

 screw cap bottles of each of the following : covered six-row barley, covered two-row barley, naked barley, wheat. 



Part A. Characteristics of Stem, Leaves and Roots. 



1. (a) Describe the stem of the barley plant, (b) Compare the stiffness of the culm 

 of barley with that of wheat, (c) How does the stiffness of the barley culm compare with 

 cats? 



2. (a) Describe the leaves of barley, (b) Compare the width of barley leaves with the 

 width of oat leaves, (c) Compare their width with wheat leaves. 



3. How does the height of barley culms seem to compare with the height of oats? 



4. How do you think the barley plant would compare with wheat as a nurse crop for 

 clover or timothy? With oats? Explain. 



5. Describe the root system of the barley plant. 



Part B. The Inflorescence. 



6. What term will describe the inflorescence of barley? 



Barleys may be divided into two classes as to the number of rows of grain. Six-row 

 barleys will be found to have six rows of grains. It sometimes happens, however, that two 

 pairs of rows overlap one another, giving rise to so-called four-row barleys. This over- 

 lapping of rows is especially marked near the top of the spike. Two-row barleys are 

 easily distinguished from six-row barleys by the flatness of the heads and the number of rows 

 of grains. 



7. Select the six-rowed, bearded, hull-less barley spike from your supplies. Remove a 

 sufficient number of grains and awl-like glumes to expose three or four of the lower joints 

 of the rachis. (a) How many grains are attached to each rachis joint? (b) Name the 

 glumes which together enclose the barley kernel, (c) How many awl-like glumes do you 

 find attached to each rachis joint? (d) How many awl-like glumes per grain? (e) What 

 name should be applied to these awl-like glumes which stand on either side of the grain? 

 (f) What is a spikelet? (g) How many spikelets per rachis joint in barleys? (h) What 

 evidence can you give to show that the foregoing answer is correct? (i) How many fertile 

 flowers per rachis joint in six-row barleys? (j) How many fertile spikelets per rachis joint 

 in six-row barley? (k) How many fertile flowers per rachis joint in two-row barleys? (1) 

 How many sterile spikelets per rachis joint in two-row barleys? 



8. Lay out in good order on a clean sheet of paper all the parts which are found on 

 a single rachis joint of six-row, bearded, hull-less barley. Write below each part its proper 

 name. Then remove the glumes and kernel a little to one side and make a careful drawing 

 of each part. Reference to Fig. 57, page 94, will aid you in this work. 



9. How does the beard of the barleys compare with the beard of wheats in the follow- 

 ing particulars: (a) Place at which it originates, (b) Direction relative to spike and to each 

 other, (c) Length, (d) Shape of cross section, (e) Barbing — as shown by rubbing the 

 fingers from the point toward the base. 



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