THE MONOCOTYLEDONOUS PLANT 79 



places the rest of the grain, which comes to lie on the side 

 of the young plantlet. The grain remains underground. 



The further development is differ- 

 ent from that of the dicotyledon. The 

 root does not form a tap root, but 

 branches almost at once; indeed in 

 the grasses generally it begins to do 

 so before it escapes from the grain. 

 The main root grows scarcely at all, 

 but a number of branches arise behind 

 its apex, making in the grasses a 

 cluster of delicate fibrous rootlets. 

 The growth of the young stem is seen 

 more advantageously in a larger grass 

 the maize. At first it is very 

 slender, but as development proceeds 

 its growing point becomes continu- 

 ally larger and more vigorous, so that 

 each node and internode become 

 larger than the preceding ones. The 

 young stem has thus the form of an 

 inverted cone (Fig. 35). This goes 

 on till the plant reaches a certain 

 height, when this continuous enlarge- 

 ment ceases and the later parts of the 

 stem are cylindrical. Several roots 

 are developed from the nodes of the 

 lower part of the stem in the case 

 of most monocotyledons ; as they 

 arise out of the normal order they are called adventitious 

 roots. 



The stem of the monocotyledon produces as a rule 

 one leaf at each node. This leaf has a very broad base, 

 which encircles the stem in large part, or sometimes 

 entirely. The leaves are said to be sheathing. 



The general requirements of the plant are not very 

 different from those of the dicotyledon and need not 



G. 35- Diagram of 

 mode of growth of 

 stem of monocoty- 

 ledon (Zea). (After 

 Sachs.) 



