6 THE STEM. 



merit. Such grasses are called bulbous, though the term tuber or 

 corm would be more nearly accurate. 



The culms of most grasses produce branches, especially from 

 the lower nodes near the ground. This branching is popularly 

 called tillering, or stooling, or mooting, and is familiar in the 

 case of wheat, oats, and rye, where one kernel not unfrequently 

 produces twenty or more culms. Tillering is favored by shallow, 

 thin seeding. Grasses are generally erect, though some are trail- 

 ing; one or more climb over trees 100 feet high; others, like 

 Leersia (rice, cut-grass), are feeble climbers or sustain themselvea 

 on plants by means of numerous hooked prickles on their leaves. 



Buds are undeveloped leaf or flower branches, and one or more 

 may be looked for at every node. The apex of the young stem 

 is covered by the young leaves. 



The nodes are usually swollen or larger than the internodes, 

 but seldom have a length very much greater than their diameter. 

 The nodes remain short when the culm is erect, but if by any 

 accident or otherwise the culm is tipped over, the nodes at once 

 become longer on the lower side, and this curves the culm towards 

 an erect position. In this way, to some extent, lodged wheat or 

 other grasses can again partially regain their former position. 

 At least, in most cases, the blossoms may be turned up from the 

 ground. 



FIG. 4. A part of a cross-section of wheat straw. A, fibro- vascular bundles ; D~ 

 fundamental tissue made of thin-walled cells with hexagonal outlines, x 75. (Mrs, 

 L. R. Stowell.) 



When quite young each internode elongates, by the multiplica- 



