EXERCISES FOR FIELD AND LABORATORY 29 



will gain in weight, or the reverse may be true when shipped from 

 humid to dry region. 



EXERCISES FOR FIELD AND LABORATORY 



Comparative Study of Cereals. All cereals are large grasses. All 

 cereals and grasses are similar in general structure. Every student should 

 have a good knowledge of the anatomy of at least one cereal. Corn, being 

 a large plant, lends itself well to such study. 



General Structure of Cereals. Before completing the work, read over 

 such parts of Chapters IV and VI as refer to general structure. 



For material use a well-developed corn plant, including roots. 



1. With a sharp knife, split the plant from the lower tip of the stem 

 to the tassel, in such a way that the buds and ear shanks are also split. 



2. Make drawing of root section, showing nodes and permanent roots. 



3. Find a section (split) showing a tiller. Make drawing, being care- 

 ful to show how tiller is attached. 



4. Make drawing of any node showing an ear bud. Indicate leaf by 

 dotted lines. 



5. Make drawing of ear, shank and ear (split) with husks. 



Note whether the number of nodes in the ear corresponds to nodes in 

 stalk, above ear. Do the husks correspond to leaf sheaths? Do you find 

 evidence of the ear stem being. a side branch, " telescoped " into the husks? 



C. Make drawing of whole plant, indicating exact number of nodes both 

 above and below ground. Indicate correctly the outgrowths from nodes, as 

 roots, buds, leaves, and ears. 

 Relation of Tassel and Ear: 



7. Sketch tassel. 



8. Sketch pair of tassel flowers (x2, i.e., double size). 



9. Sketch section of central portion of tassel. 



10. Sketch cross-section of ear. 



11. Sketch kernel showing chaff at base (x2). 

 Write up brief report as follows: 



Describe relation of ear and tassel. Relation of ear branch and a tiller. 

 How many ear buds?' Ears? Leaves? Husks on an ear? 



Comparing the Spikes and Flowers. All spikes of cereals and 

 grasses are similar in structure, though it may not appear so at first. 

 Lay out in a row: 



1. Spikes of grasses, as timothy, rye-grass, etc. 



2. Spikes of cereals, as wheat, oats, barley and rye. 



3. Spikes of corn, as tassel and ear. 



(a) Determine what a spikelet is, using oats for this study. Draw all 

 the parts of a spikelet and label same (drawing 3 times enlarged) . 

 ( 6 ) Draw a wheat spikelet. 



(c) Draw a barley spikelet. 



(d) Now isolate a spikelet from each of the spikes which you have laid 

 out as above. See if you can identify analogous parts in each case. 



Write a concise statement defining (1) spike; (2) spikelet; and (3) 

 flower. 



Compare the central spike of a corn tassel and an ear of corn, and 

 work out the analogous parts. 



To what does the hull of oats correspond in the wheat flower? 



How many kernels per spikelet are usually found in wheat, oats, barley, 

 rye, corn, millet, brome-grass, and rye-grass? 



