16 PANIC ACE^. 



rarely subherbaceons, short, very broad, obtuse or emarginate, 2- 

 lobed, the 2 outer empty sometimes thicker, the third hyaline, 

 often protecting the short palea, the terminal or floral glume 

 hyaline, often bifid; the palea equally broad, but not divided. 

 Staminodia 0. Style very long, threadlike, briefly parted at the 

 apex, rarely separated to the base, stigmatic hairs very short. 

 Grain, on a short stipe, subglobose or obcompressed, hard, slightly 

 protected by the delicate glumes and palea? or enclosed or covered 

 by a variety of acute or subherbaceons glumes. 



The terminal staminate panicle with a long showy peduncle, 

 in some varieties in cultivation bearing some pistillate flowers 

 mixed with the staminate. Staminate flowers at the apex of the 

 pistillate spike are not uncommon. The pistillate spikes usually 

 solitary or branching in the axils of the leaves, the styles when mature 

 much exserted, pendulous; at maturity the pistillate spike is long, 

 hard, and entirely covered with the palealike sheaths. It is excep- 

 tional in the whole order, by the manner in which its pistillate 

 spikelets are densely packed in several vertical rows around a central 

 spongy or corky axis. How much of this arrangement is due to 

 changes brought about by cultivation and selection can only be a 

 matter of conjecture. 



Species 2, possibly 3, all American. 



1. Z. Mays L. Sp. PI. 971 (1753). Annual. Most likely a 

 native of tropical America; extensively cultivated in the warmer 



temperate zones, exceedingly variable, 

 0.5-6 m. high, not known in a wild 

 state. A very valuable well-known 

 cereal and fodder-plant. See Vol. I. 

 2. Z. canina S. Wats. Proc. Am. 

 Acad. 26 : 160 (1891). 



Culms several from the same root, 



ascending, branched, 2-4 m. high. 



Y^^. %.-Zea Mays, staminate ^^^aves like those of Zea Mays. Stami- 



spikelet. x 3. (Richardson.) i:ate racemes often elongated and 



drooping. Spikelets 2-4 (usually 3) at each node, one or more 



short-pedicelled ; empty glume 3-5-nerved, bicarinate. Pistillate 



