34 PASTURE PLANTS AND PASTURES OF N.Z. 



best way to introduce the grass would be to secure 

 a supply of rhizomes, chop them up and harrow or 

 trample them into the soil. 



(2) Poa pratensis. This is also a common twitch : It 

 is described on page 22. 



(3) Festuca saburicola. Chewings Fescue is another 

 twitch. It is described on page 16. 



(4) Agrostis alba is often called Water Twitch, but is 

 better known under the names of Creeping Bent, Fiorin, 

 Red Top, etc. It is described on page 20. 



(5) Holcus mollis.. Creeping Fog, is one of the worst 

 Twitches we have, but fortunately it is not very common 

 in most districts. It is very like Yorkshire Fog in its over- 

 ground parts, having the same velvety leaf, red and white 

 leaf sheath, and pinkish feathery flower head. Underground, 

 however, it displays thick and strong creeping stems that 

 are very difficult to kill. The leaves are disliked by stock 

 wherever better grasses are available, and on the whole this 

 twitch seems to have no merit of any kind. 



(6) Avena bulbosa. Onion rooted twitch. This grass 

 is, above ground, much like Tall Oat Grass (v. p. 27). 

 Below ground, however, it displays a very characteristic 

 structure. There is a string of 6 or 8 onion-like swellings. 

 These are really knots, and vary in size from that of a pea to 

 that of a hazel nut. Each knot is capable of independent 

 growth when broken off from the parent stem. The grass 

 is not really a twitch because it has no rhizomes, and it will 

 not spread at all if it is not disturbed. Ploughs and harrows, 

 however, break up the strings of knots and scatter them far 

 and wide, so that in arable land the grass soon takes possess- 

 ion. It is very difficult to eradicate, for harrows cannot 

 drag the knots to the surface in the same way as they do 

 ordinary long rhizomes. The only way is to continuously 

 cultivate the ground where it occurs, destroying the green 



