444 BRITISH FLOWERING PLANTS chap, ii 



Triodia 



The genus takes its name from the three-toothed 

 flowering glume. Our one species, T. decumbens, is 

 found in dry pastures and on moors. 



KCELERIA 



K. cristata has a slender silvery panicle. The 

 flowers are homogamous ; the anthers bluish-black. 

 The • genus is named after Koeler, a German writer 

 on Grasses. 



Sesleria 



S. coerulea. — A Central and South European species 

 found in hilly pastures, especially in limestone districts. 

 The flowers are protogynous. The genus takes its 

 name from Sesler, an Italian botanist. 



Sesleria is one of the plants which has stomata on the 

 upper surface of the leaf. In the morning, or if the 

 weather is damp, the leaf is flat ; but as the sun rises 

 and the air becomes drier, the sides rise and at last 

 the two edges almost meet, thus protecting the leaf 

 from too rapid transpiration. The movement is eff'ected 

 by a special tissue of motor cells on each side of the 

 mid-rib, comparable to those illustrated on p. 433, 

 Many other grasses protect themselves in a more or less 

 similar manner. 



Phragmites 



P. communis (Eeed). — As a rule the florets in a 

 spikelet are close together, but in this species there is 

 a slight interval, clothed with long silky hairs, forming 

 a parachute. The stem is round, and, as well as the 

 leaf-sheath, quite smooth at the surfaces of contact. 

 The result is, that in a high wind the leaf turns partly 

 round, so as to fly with the wind, like a pennon. Even 

 if the sheath splits a little, this does not injure the 

 plant. 



