,52 ROUND THE YEAR 



In some large grasses, such as cereals, these additional 

 or adventitious roots can be seen at times to issue 

 from a knot two or three inches above the ground. 

 They serve not only as channels for the supply of 

 nourishment, but as stays, like the stout wires which 

 are employed to secure a telegraph-pole. 



I have said that the diaphragms probably increase 

 the rigidity of the haulm ; in the great haulms of a 

 Bamboo they certainly do stiffen and strengthen the 

 tube to a notable extent, but here they are of particu- 

 larly firm texture. An excellent model of the grass- 

 haulm can be made by procuring one of the Bamboo 

 rods now sold in the shops for fishing-rods and 

 curtain-poles, and sawing it in half along its length. If 

 a piece of Bamboo is knocked to bits against a stone, 

 some notion may be got of its great strength, and of 

 the way in which the diaphragms prevent splitting and 

 crushing. The Bamboo is a true grass, and in all 

 essentials of structure reproduces on a large scale the 

 features of our small native grasses. 



If we try to cut a piece of Bamboo with a knife we 

 are reminded of another peculiarity of the grasses. 

 The Bamboo cuts very badly, with a harsh gritty feel, 

 and quickly blunts the knife. The hard, glossy surface 

 is particularly unpleasant to cut, as well may be, 

 seeing that it is largely composed of flint. The glossy 

 surface of a Wheat-straw contains much flint too, and 

 in various degrees all grasses and almost all parts of 

 them are flinty. By very cautious charring, or by 

 removal of the organic matter in other ways, it is 

 possible to get small pieces of grass which show the 

 flinty particles under the microscope. They some- 



