VEGETATIVE ORGANS 



CHAPTER II. 



THE VEGETATIVE ORGANS. 



Grasses vary very much in their habit. Some grasses grow 

 erect forming tufts and others form cushions with the branches 

 creeping along the ground. (See figs. 5 and 6.) We usually find 

 all intermediate stages from the erect to the prostrate habit. 

 Underground stems such as stolons and rhizomes occur in some 



grasses. Grasses 

 of one particular 

 species generally 

 retain the same 

 habit but this 

 does not always 

 hold good. For 

 example Tragus 

 racemosus grows 

 with all its 

 branches quite 

 prostrate in a 

 poor, dry, open 

 soil. If, on the 

 other hand, this 

 happens to grow 

 in rich soils, or 

 amidst other 



plants or grasses, 

 it assumes an 

 erect somewhat 

 tufted habit. 



Andropogon con- 

 tortus and Andropogon pertusus are other grasses with a tendency 

 for variation in habit. Plants that are usually small often attain 

 large dimensions under favourable conditions of growth. Ordi- 

 narily the grass Panicum javanicum grows only to I or 2 feet. (See 

 fig. I.) The same plant in a good rich soil grew to about 6 feet in 

 four months. (See fig. 7.) 



Some grasses are annual while others are perennial. It is often 

 difficult to determine whether a certain grass is annual or perennial. 

 But by examining the shoot-system this can be ascertained easily. 

 In an annual all the stems and branches usually end in inflor- 

 escences and they will all be of the same year. If, on the other 

 hand, both young leafy branches and old branches ending in 

 inflorescences are found mixed, it must be a perennial grass. The 

 presence of the remains of old leaves, underground stolons and 

 rhizomes is also evidence showing the perennial character of the 

 plant. 



Grasses are eminently adapted to occupy completely large 

 areas of land. They are also capable of very rapid extension over 

 large areas, on account of the production of stolons, rhizomes and 

 the formation of adventitious roots. 



FlG. 5. — Eleusine cegyptiaca. 



