82 THE TRUE GRASSES. 



nothrix latifolia Schult.), with culms 1-1.5 m. high, leaves 

 broad-lanceolate, is an ornamental grass used for cover- 

 ing roofs of houses in the Argentine Eepublic, where it 

 is native ; P. Japonicum Triu. ( Gymnoth. Japonica), a low- 

 growing species with linear leaves, is also an ornamental 

 grass. Amphochceta Anderss. includes a species with 

 spikes in panicles ; Sericura Hasskarl, is a Malayan 

 species with very long bristles. 



Sec. IV. Beckeropsis (Fig. & De Notar, as a genus) has 

 only one involucral bristle to each spikelet ; spikes 

 in panicles. Distinguished from Chamceraphis by the 

 persistent pedicels of the spikelets. 



70. (15) Plagiosetum Benth. One to two, narrow, 

 acute spikelets within each involucrum. 



Species one (P. refrcuctum Benth.), in Australia. 



71. (18) Chamseraphis Brown (Paratheria Griseb.). 

 Spikelets lanceolate, in simple or slightly branched 

 racemes, on short pedicels which fall off with the spike- 

 lets. First empty glume very short. 



Species five ; four in tropical Asia and Australia, one 

 in the West Indies and Brazil. 



72. (20) Xerochloa Brown. Subtending bracts of the 

 spikes husk-like, distichous ; axis of the spike short, with 

 a chaff-like continuation beyond the spikelets. Spikelets 

 two-flowered ; flowering glume of flower very narrow. 



Species three, in Australia. 



73. (21) Stenotaphrum Trin. (Diastemanthe Steud.). 

 Spikelets 2-4, forming a short, partial spike, embedded 

 in the alternate notches of the broad rachis of a spike- 

 like panicle ; axis of the spike with a chaff-like prolonga- 

 tion. Spikelets two-flowered, first empty glume small. 

 Creeping grasses with compressed culms and flat, diver- 

 gent leaves. 



Species three or four, one of which, St. Americanum 

 Schrank (Fig. 33), is widespread in the tropics and sub- 

 tropical regions, and is useful for holding the sand on 

 the banks of rivers. The rhizome is used in South 

 America as a diuretic. The other species occur on the 

 islands of the Indian and Pacific oceans. 



