LESSON XI 



PAIRED SPIKELETS WITH HARDENED GLUMES 

 AND THIN LEMMAS 



In the sorghum tribe, which we are about to study, 

 the spikelet, as in the millet tribe, falls entire and is 

 dorsally compressed, but the glimaes are hardened 

 and the lemmas thin, while in the millet tribe the 

 glumes are thin and the fertile lemma and palea are 

 hardened. The glumes entirely inclose the two 

 florets. The midnerve of the first glume is com- 

 monly suppressed, while a pair of nerves near the 

 margin is often prominent and sometimes keeled, or 

 even winged. The second glume may be like the 

 first or the midnerve may be slightly keeled. The 

 lower floret consists of an empty lemma only, the 

 upper of a perfect flower with a small thin often 

 awned lenama (sometimes so small as to appear 

 like a bit of membrane at the base of the awn) and a 

 minute palea (sometimes suppressed). 



Examine Fig. 73, A, and compare it with Figs. 21 

 (p. 30), 22 (p. 31), 30 (p. 40), 40 (p. 49), 52 (p. 61), 

 and 53 (p. 62). In all the figures referred to, fertile 

 spikelets are associated with sterile ones. These 

 are grouped in various ways. In the sorghum tribe 

 the typical arrangement is a jointed raceme with a 

 sessile perfect spikelet and a pediceled sterile spikelet 



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