DESCRIPTIONS OF TRIBES AND GENERA. 37 



entirely enclosed by the ovate or spherical, ivory-like 



sheath of the subtend ing bract 7. Coix. 



C. $ and ? spikelets in the same spike (at least in the lat- 

 eral spikes), the loivest empty glume of the 9 spikelets 

 indurated. 



a. The covering of the false fruit chiefly formed by 

 the rachis, its opening in front closed by the nar- 

 row empty glume 3. Tripsacum. 



b. The covering of the false fruit chiefly formed by 

 the first empty glume, which is appressed to the 

 narrow joint of the axis to which it is attached on 

 the inner side. 



a. The terminal spikes $ , the lateral ones androg- 

 ynous or $ 4. Polytoca. 



(3. Spikes all monoecious. 



I. Several $ spikelets above the $ , the latter 

 without membranaceous appendages. 



5. Chionachne. 

 II. One $ spikelet above every $ , each of the 

 latter provided with an open membrana- 

 ceous appendage (the hardened outer 

 glume) 6. Sclerachne. 



Note. — In the explanations of all the following figures the letters are 

 used as follows: A, entire inflorescence or part of the same; B, 

 spikelet ; C, empty glumes (iu order d, C 2 , C 3 , C 4 ) ; D, flowering 

 glume ; E, palea ; F, flower ; G, lodicules ; J, pi~til ; K, fruit or grain. 

 Special letters are explained in the descriptions. 



1. (37) Euchlsena Schrad. {Reana Brign.). Two $ 

 spikelets to each joint of the rachis (one sessile, the 

 other pedicellate), both two-flowered with membrana- 

 ceous glumes ; ? in two-ranked spikes (apparently one- 

 ranked). These spikes are fasciculate in the leaf-axils ; 

 the joints of the axis to which they belong are trape- 

 zoids, so that as they fall off, the obliquity of the upper 

 surface of one alternates in direction with that above or 

 below it. The edges of the cavity embrace the first car- 

 tilaginous empty glume, forming with it at maturity a 

 smooth cartilaginous capsule or false fruit. Styles pro- 

 longed far beyond the leaf at the base of the spikelet, and 

 two-cleft at the end. Tall annuals with verv broad leaves. 



