8 ROOTS AND STOLONS [CH. 



Aira canescens (Grey Hair-grass). 



A. prcecox (Early Hair-grass). 



A. caryophyllea (Silvery Hair-grass). 



Nardus stricta (Moor Mat-grass). 



Hordeum murinum (Wall Barley). 



H. maritim/wm (Sea Barley). 



Lolmm perenne (Rye-grass). 



L. temidentum (Darnel). 



Bromiis arvends (var. mollis). Field Brome. 



Featuca ovina (Sheep's Fescue). 



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



Brka media (Quaking-grass). 



Poa maritima (Sea Poa). 



P. anniiM (Annual Meadow-grass). 



P. compressa (Flattened Meadow-grass). 



P. alpina (Alpine Poa). 



P. hvlbosa (Bulbous Poa). 



Triodia decumbens (Heath-grass). 



Kmleria cristata (Crested Koeleria). 



The roots of our grasses are almost always thin and 

 fibrotis 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 ease 

 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 hulbosus (Fig. 3), Poa bullosa, Phleum pratense 

 and P. Bcehmeri, Arrhenatkerum 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 tuber 

 or bulb results ; this is especially apt to occur in dry sandy 



