DESCRIPTIONS OF TRIBES AND GENERA. 151 



generally cultivated in Spanish South America, forming 

 living fences. The culms are used for laths, and, when 

 split, for woven work. The leaves are used for roofing, 

 and the rhizomes are employed as a diuretic. It is also 

 grown as a decorative plant. [There is a cultivated 

 variety which has its broad leaves striped with longitu- 

 dinal white bands.] 



Fossil Species. — Many rhizomes, culms, and leaves of 

 A. Goepperti Heer are found in the tertiary of Europe 

 and N. America which show points of agreement with 

 the living species. A. Groenlandica Heer occurs in the 

 upper chalk formation of Greenland. 



217. (212) Phragmites Trim (Czernya Presl). Spike- 

 lets loosely many-flowered, lowermost flower £ , the 

 others usually £ ; rarely the plants are dioecious, but 

 without any striking distinction between the sexes ; 

 flowering glumes naked, long-acuminate-pointed. Habit 

 of Arundo, but with the culm usually not so stout. 



Species three, one cosmopolitan, a second in tropical 

 Asia, and a third (dioecious) in the Argentine Republic. 

 P. communis Trin. is a reed-like grass with culms 1-3 m. 

 high and expanded, usually purple or violet colored 

 panicles. It grows in standing or sluggish water and 

 in swamps, is gregarious in habit, and is distributed 

 throughout the world. The culms are used for roofing 

 and as laths for covering walls about to be plastered, 

 for matting, basket-work, mouth-pieces of musical in- 

 struments, weavers' spools, etc. ; the young shoots are 

 fed to horses, and an infusion of the root is used as a 

 diuretic. 



Fossil Species. — Ph. Ungeri Stur. Rhizomes in the 

 lacustrine strata in Hungary. Ph. ceningensis A. Br. is 

 found in the tertiary of Europe, the polar regions and 

 X. America. Ph. cretaceus Lesq. in the cretaceous forma- 

 tion of N. America. 



Sub-tribe D. — Triodieae. 



Flowering glume usually 2-3-toothed ; middle tooth often awned or 



awn-like. 



218. (205) Blepharidachne Hack, in Monogr. Androp.. 



