90 FIRST BOOK OF GRASSES 



spikelet removed from its joint; C, the joint from 

 which a spikelet has been removed; and E, a diagram 

 of the rachis. Compare the joints with those of 

 Manisuris (Fig. 76). Note that in Tripsacum the 

 pistillate part is a simple spike with no vestige of a 

 second spikelet. The structure of the spikelet is 

 similar to that of spikelets of the sorghum tribe, hav- 

 ing firm glumes (the first hard and like the rachis 

 joint in texture), a thin sterile lemma, and a very 

 thin fertile lemma and palea. The staminate spike- 

 lets are in pairs (Fig. 80, F) and one of each pair is 

 usually on a very short pedicel. The glumes are 

 much like those of different species of Andropogon; 

 both florets are staminate, their lemmas and paleas 

 thin. 



Indian corn, or maize (Zea Mays), the most 

 highly specialized grass known, is believed to be 

 related to Tripsacum. It is monoecious, but the 

 staminate and pistillate spikelets are borne in distinct 

 inflorescences. The staminate spikelets are in pairs 

 on a slender rachis forming racemes, these arranged 

 in a panicle, the "tassel," at the summit of the culm. 

 The pistillate spikelets are in pairs, crowded in 8 to 

 16 rows (rarely more) always an even number, on a 

 greatly thickened compound axis, the "cob," borne 

 in the axils of the leaves and enveloped in numerous 

 leafy bracts ("husks"), the long styles (the "silk") 

 protruding from the summit, the whole called the 

 "ear." The staminate spikelets (Fig. 81, C) are 

 much like those of Tripsacum and contain two 



