29 



3. Lower sheaths more or less covered with a coat of wool. 



Panicles usually capitate '. , 4 



Lower sheaths glabrous, or minutely pubescent or 

 tomentose. Panicles not capitate 7 



4. Panicle loosely contracted D. zeyheriaiia. 



Panicle compact spike-like or capitate 5 



5. Spikelets 10-12 lin. long in large heads 2-2^ in. long. 



D. maerocephala. 

 Spikelets smaller, 4-8^ lin. long 6 



6. Spikelets 6-8^ lin. long. Glumes narrow, long and 



acutely acuminate D. lanata. 



Spikelets 4-7 lin. long. Glumes rather broad, shortly 

 acuminate or mucronate D. lupulina. 



7. Spikelets awnless, or awn reduced to a mucro 8 



Spikelets distinctly awned 9 



8. Spikelets 2 lin. long. Awn reduced to a mucro from a 



sinus D. inermis. 



Spikelets turgid, 4-6 lin. long, awnless ... D. decumbens. 



9. Dwarf plants. Blades not exceeding 2 inches. Culms 



1-2 noded 10 



Not dwarf 13 



10. Valve lobes obtuse, hyaline ... Jl 



Valve lobes mucronate, or long setaceously acuminate 12 



11. Perennial. Valve lobes ciliate D. purpurea. 



Annual. Valve lobes truncate, not ciliate ... D. tenella. 



12. Spikelets 5-6 lin. long. Valve lobes mucronate ... 



D. pumila. 



Spikelets 2-2| lin. long. Valve lobes long, setaceously 



acuminate D. curva. 



13. Spikelets 2-4| lin. long 14 



Spikelets about 6 lin. (rarely to 10 lin.) long. Rather 



coarse grasses 16 



14. Spikelets 2-2| lin. long. Valve lobes long, setaceously 



acuminate D. curva. 



Spikelets 3^-4^ lin. long. Valve lobes not setaceously 

 acuminate 15 



15. Suffrutescent. Lower sheaths coriaceous 



D. suffrutescens. 

 Herbaceous. Lower sheaths thin D. glauca. 



16. Inflorescence a distichous linear spike D. disticha. 



Inflorescence a true contracted panicle 17 



