OF THE GRAMINE^E. 597 



Qne tuber of the T. repens ; no root was pro- 

 duced, the stem being raised from the soil. In 

 April last, I planted a part of the stem, nine inches 

 in length, of Poa triviaiis, in a moist situation, 

 the lowest tuber just beginning to send forth 

 roots. At midsummer, one hundred and seventy 

 plants and branches were produced, covering about 

 a square yard of surface ! 



In the more erect species, (as the Cerealia), the 

 stem generally dies, after producing ripe seeds ; 

 and these have therefore, though inaccurately, been 

 accounted annual or biennial : but this is by no 

 means uniformly the case, and a more exact at- 

 tention to what really happens, renders it pro- 

 bable, that the whole of the Graminese are, under 

 certain circumstances, perennial # . 



Plate XIV. fig. 4. represents a specimen of T. hi- 

 bernum, with young plants of the third year shot 

 from the tubera of the stubble of the past season. 

 This property is common to the cultivated species 

 of barley and oats, which I have repeatedly obser- 

 ved produce plants during a moist autumn from the 

 stubble, when the field had been sown with hay 

 seeds; and in those spikes whose shoots were observ- 

 able among the crop early in the following season, 

 the seeds ripened some time sooner than those of 



p P 3 



* Poa rigida is the only exception I have hitherto met 

 with : whether this be owing to the dry situation in 

 which it grows, remains to be ascertained, 



