HOW TO KNOW THE GRASSES 



€b. Spikelets without awns; cultivated plants. Fig. 341. 



SUGAR CANE Saccharum oiiicmarum L. 



Perennial; tall stout plants, with culms 

 3 — 5 m. tall and up to 3 cm. thick. The 

 stiff, elongated leaves have very sca- 

 brous cutting edges. Panicles large and 

 plumelike, 20 — 60 cm. long. The ra- 

 cemes break up into individual joints 

 when ripe, with a pair of spikelets at- 

 tached to each joint. Sugar cane is 

 widely cultivated in the tropics for the 

 production of sugar, but in the United 

 States is grown only in the southern end 

 of the Mississippi Valley and in Florida. 

 The plants seldom bloom. 



Eiianthus ravennae (L.) Beauv. (RAVENNA GRASS) has a large, 

 plumehke panicle, up to 60 cm. long, and slender culms up to 4 m. tall. 

 Cultivated for ornament and hardy in the southern half of the country. 



7a. Pedicels and rachis joints thickened at the upper ends, closely 

 pressed together or united; spikelets awnless 8 



7b. Pedicels and rachis joints not evidently thickened, not pressed to- 

 gether nor united; spikelets awnless or owned 9 



Ba. Perfect spikelet spherical, with a rough pitted surface; rachis joint 

 and pedicel united. Fig. 342. 



Hackelochloa granularis (L.) Kuntze 



Figure 341 



Figure 342 



Annual; tufted; culms 30 — 100 cm. tall, much 

 branched. The culms have numerous axillary 

 racemes; sheaths and culms covered with hairs 

 which arise from Httle blisters. The spikelets 

 are borne in spikes or racemes, 1 — 2 cm. long, 

 the individual spikelets being 1 — 2 mm. long. 

 The racemes break up into individual joints, 

 each bearing a sessile perfect spikelet which is 

 blackish, and a strongly laterally compressed 

 and winged staminate spikelet, which is green 

 or reddish in color. This unusual grass is a 

 native of the Old World tropics, but has been 

 introduced into our southern states. It may yield 

 some forage. Fall. 



178 



