32 



FIRST BOOK OF GRASSES 



while the sterile spikelets are many-flowered and 



awnless. 

 We shall next examine a grass having unisexual 



spikelets (see Lesson III, page 23), the two forms 

 borne on different plants (dioecious). 

 (In the group with relatively simple 

 spikelets which we are now studying 

 there are no monoecious grasses). 

 In Fig. 23 are shown the pistillate 

 and staminate spikelets of salt-grass 

 (Distichlis spicata). They differ but 

 little in appearance and are both 



FIG. 23. Pistillate 

 and staminate 

 spikelets of Dis- 

 tichlis spicata. 



borne in narrow 

 panicles. [9 sig- 

 nifies female, d* 

 male. These signs 

 are commonly 

 used to indicate 

 pistillate and sta- 

 minate plants, 

 respectively.] 



In Fig. 24 are 

 seen the strikingly 

 diverse staminate 

 and pistillate spikelets of another dioecious species 



Fig. 24. Staminate and pistillate spikelets of 

 Scleropogon brevifolius. 



