10 



4. Spikelets in groups of two to six at each point of the main axis, 

 each group falling off entire; flowering glumes usually awn- 

 less. (Cathestecum may be looked for here.) 



Tribe III. osterdamie.e. (See page 25.) 



4. Spikelets falling off singly from the ultimate branches of the 



inflorescence 5 



5. Flowering glumes of the perfect flower membranaceous and (in 



American species) awned. 



Tribe IV. tristegineje. (See page 30.) 



5. Flowering glumes of the perfect flower cartilaginous, coriaceous 



or chartaceous and awnless or (in Eriochloa) with a short, 



straight awn Tribe V. panice2e. (See page 30.) 



Tribe I.— MAYDEjE. 



Spikelets unisexual, the staminate forming a part of the inflo- 

 rescence with the pistillate, or each in a separate inflorescence on 

 the same plant; flowering glumes hyaline or much less firm in 

 texture than the outer ones; axis of the female spikelet usually 

 articulated. 



A small tribe, numbering only sixteen species classed 

 in seven genera. The}^ are nearly all natives of the 

 Tropics, chiefry in the Old World. Indian corn, or 

 maize, is our best-known example of the Maydeae. 



key to the genera of the maydeje. 



1. Staminate spikelets in an upper, pistillate in a lower and dis- 

 tinct inflorescence 2 



1. Staminate spikelets above, the pistillate below in the same 



inflorescence 3. Tripsacum 



2. Pistillate spikes many-flowered, enveloped in broad, leaf-like 



bracts; the staminate spikes numerous in terminal pani- 

 cles 3 



2. Pistillate spikes usually reduced to a single spikelet, staminate 



spikes solitary 4. Coix 



3. Pistillate spikes axillary, fasciculate, distinct, axis of each 



articulate 1. Euchl.exa 



3. Pistillate spikes axillary, grown together, forming a compound 

 spike with a much thickened, continuous axis 2 Zea 



