32 INDICATOR-PLANTS [CH. 
without reference to the quality of the soil, that they are 
not indicative. The latter are often termed ruderal or 
vagabonds (see p. 29). Without attempting too ngid a 
classification of Grasses in this connection—which would 
be premature in this early state of our knowledge—the 
following remarks are at least generally true. 
A few grasses are Indicators of chalk and limestone— 
e.g. Briza media, Keleria cristata, and the exotic species 
Stipa pennata and Melica ciliata. 
The following are said to indicate a sufficiency of 
potassium salts, 
In moister soils. 
Digraphis arundinacea. Arundo Phragmites. 
Phleum pratense. Molinia cerulea. 
Avena pubescens. Glyceria fluitans. 
In drier soils. 
Anthoxzanthum odoratum. Dactylis glomerata. 
Alopecurus pratensis. Cynosurus cristatus. 
Agrostis alba. Poa pratensis. 
Holcus lanatus. P. trivialis. 
Arrhenatherum. P. compressa. 
Keleria cristata. Festuca elatior. 
Briza media. Lolium perenne. 
Grasses like Bromus arvensis indicate the existence of 
clay in the soil. 
While the following are indicative of sand, 
Aira caryophyllea. Festuca ovina. 
A. precox. Bromus sterilis. 
A. canescens. 
