GRASSES OF BRITAIN. 157 



twice the length of the spikelet, and furnished with teeth directed 

 downwards. 



This grass is not strictly a British plant, although found occa- 

 sionally in Surrey, Suffolk, and Norfolk. It is a native of Nor- 

 way, Sweden, France, Prussia, Austria, Switzerland, Italy, Portu- 

 gal, Spain, Russia, North Africa, and the United States. It grows 

 naturally on sandy soil in cultivated districts, but of no agricultural 

 importance. In some countries it becomes a very troublesome weed. 

 It produces an abundance of seed, of which small birds are very fond. 



Flowers in July and August, and ripens its seed in about the end 

 of September. 



The accompanying figure was taken from a specimen gathered in 

 Suffolk. 



Explanation of Plate LXVIII. Setaria viridis^ natural size. 



Fig. 1. Rachis, with the sjjikelets removed, leaving the rough bristles natural size. 



2. Spikelets showing the long bristles with erect teeth. 



3. Glumes very unequal. 



4. Lowermost floret of one palea. 



5. Upper floret of two pales. 



6. Ovarium, pistils, and stamens. 



7. Ligule of upper sheath. 



