8 ROOTS AND STOLONS [CH. 



Aira canescens (Grey Hair-grass). 



A. prcecox (Early Hair-grass). 



A. caryophyllea (Silvery Hair-grass). 



Nardus stncta (Moor Mat-gi-ass). 



Hordeum murinum (Wall Barley). 



H. maritimum (Sea Barley). 



Lolium pereime (Rye-grass). 



Z. temulentum (Darnel). 



Bromus arvensis (var. mollis). Field Bromc. 



Fe.^tuca ovina (Sheep's Fescue). 



F. Myurus (Rat's-tail Fescue). 



Briza media (Quaking-grass). 



Poa maritima (Sea Poa). 



P. annua (Annual Meadow-grass). 



P. compressa (Flattened Meadow-grass). 



P. alpina (Alpine Poa). 



P. hidbosa (Bulbous Poa). 



Triodia decumbens (Heath-grass). 



Kceleria cristata (Crested Koeleria). 



The roots of our grasses are almost always thin and 

 fibrous and are adventitious from the nodes, frequently- 

 forming radiating crowns round the base and easily pulled 

 up, and usually broken in the process; but in the case 

 of a few moor grasses — especially Nardus (Fig. 2) and 

 Molinia — the roots are so tough and thick {stringy) as to 

 resist breakage very efficiently. In stoloniferous grasses a 

 similar difficulty of removal may be caused in a slighter 

 degree by the underground stems. In a few cases, e.g. 

 Alopecurus hulhosus (Fig. 3), Poa hidbosa, PJdeum pratense 

 and P. Boehmeri, Arrhenatheruni avenaceum, and to a 

 slighter extent in Poa alpina and one or two others, the 

 lowermost internodes and sheaths of the stems may be 

 swollen and stored with food-materials, and a sort of Uiber 

 or bulb results ; this is esj)ecially apt to occur in dry sandy 



