58 THE BOOK OF NATURE STUDY 



It is, unlike the Cock's-foot, one of the best Grasses for producing 

 an even sward, by means of its short creeping stems, or stolons. 

 The Sweet Vernal (Anthoxanthum odoratum) also flowers early. It 

 is mainly this grass which gives the sweet scent to newly mown 

 hay. The spikelets cover the entire surface, and each has but 

 one perfect flower, with two, instead of three stamens. 



The Meadow Fescue (Festuca elatior) is a large grass, often 

 over three feet high. The sheath is red, and there is no ligule. 

 It may be distinguished from the Brome Grass, which in some 

 respects it closely resembles, by the split sheath. The Meadow 

 Grass (Poa pratensis) is a perennial with long stolons. It is of 

 great value for " bottom grass," but yields only thin hay. It 

 has four to five flowers in each spikelet. 



Grasses are not the only plants found in meadows. Clovers 

 and a certain number of plants, useless as far as food is concerned, 

 and therefore called "Weeds," form a certain proportion, though 

 a varying one, of all grassland. The Clovers are leguminous 

 plants, and of great value from the power they possess of enriching 

 the soil with nitrogen, through the bacteria present in the tubercles 

 of their roots. These bacteria have the power of "fixing" the 

 free nitrogen of the air. The four Clovers most common in 

 meadows are 



1. The White Clover, which flowers from May to October, 

 and is most abundant in soil containing lime. 



2. Broad or Red Clover, which is found practically everywhere. 



3. Perennial Clover or Cow Grass, also very common. 



4. Alsike Clover, which is found in moist soil. 



The structure of the Clover flower differs from that of the 

 Bean or Pea in the fact that the petals and stamens are united 

 to each other. 



EFFECT OF MANURES ON GRASSLAND. At the Rothamsted Ex- 

 perimental Station, experiments on the effect of certain manures on 

 grassland were begun in 1856, and have been continued without 

 intermission. These have been tried on some twenty plots of 

 ground, each about a quarter of an acre in extent. The land chosen 

 has been under grass for some centuries, and as far as is known no 

 fresh seed has been sown. Since 1874 there has been no grazing 



