TRISTEGINE.E. 



76 



any cluster fertile, others sterile, spikelets finely pubescent, with a 

 sheath of very short hairs at the base, linear-lanceolate, 5 mm. long, 

 third glume elliptical-lanceolate, 5-nerved, as long as the spikelet, 

 with a straight awn about half its own length ; palea elliptical when 

 spread, 5 mm. long, with 2 nerves near the middle. Grain linear, 

 compressed, 1 mm. long. 

 Mexico, Schaffnej- 1070. 



Fig. 19. — Schaffnera gracilis. A spikelet dissected. (Scribner.) 



Tribe IV.— TRISTEGINE^. 



Spikelets all similar. 1-2-flowered, in panicled racemes, falling 



off singly from the ultimate branches of the continuous axis of the 



panicle. Empty glumes three, herbaceous or chartaceous, the first 



