11] INDICATOR-PLANTS 33 
And only if the sandy soil is moist and of better quality, 
owing to a certain proportion of humus, the following, 
Anthoxzanthum odoratum. Arrhenatherum avenaceum. 
Agrostis alba. Avena pubescens. 
Dactylis glomerata. Poa pratensis. 
That the soil contains considerable quantities of 
common salt—sodium chloride—may be inferred if the 
following grasses occur, 
Psamma arenaria. Hordeum maritimum. 
Elymus arenarius. Agropyrum junceum, &e. 
The existence of much humus is indicated by such 
shade grasses as 
Melica wniflora. Bromus giganteus. 
M. nutans. B. asper. 
Milium effusum. Brachypodium sylvaticum. 
Whereas soils known as “sour,” though containing 
much vegetable remains, may be suspected if the following 
grasses abound on them, 
Aira cespitosa. Alopecurus geniculatus. 
Nardus stricta. Molinia cerulea ; 
especially if sedges and rushes coexist with them. 
When cuttings are made in forests, such grasses as 
the following are very apt to appear, and may do harm to 
young plants, 
Festuca ovina and varieties. Holeus mollis. 
Agrostis alba. Aira flexuosa, &e. 
The grasses more especially indicative of particular 
classes of forest-soils are chiefly the wood-species (see 
W. 3 
