Il] INDICATOR-PLANTS 33 



And only if the sandy soil is moist and of better quality, 

 owing to a certain proportion of humus, the following, 



A nthoxanthmn 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, Hordewn maritimum. 



Elymiis arenarius. Agropynim junceiim, &c. 



The existence of much humus is indicated by such 

 shade grasses as 



Melica uniflora. Bromus giganteus. 



M. nutans. B. asper. 



Milium effusum. Brachypodiwm sylvaticum. 



Whereas soils known as "sour," though containing 

 much vegetable remains, may be suspected if the following 

 grasses abound on them, 



Aira coespitosa. Alopecurus geniculatus. 



Nardus striata. Molinia ccerulea ; 



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, 



FestViCa ovina and varieties. ffolcus mollis. 



Agrostis alba. Aira fleosuosa, &c. 



The grasses more especially indicative of particular 

 classes of forest-soils are chiefly the wood-species (see 

 w. 3 



