GENERA OF GRASSES OF THE UNITED STATES. 287 
races of American aborigines, from Peru. to middle North America. 
Several races of corn are grown in the United States, the most im- 
portant being dent, the common commercial field sort, flint, sweet, and 
pop. Pod corn (Z. mays tunicata Larr.), occasionally cultivated as a 
curiosity, is a variety in which each kernel is enveloped in the 
elongate floral bracts. A variety with variegated leaves (Z. mays 
japonica Korn.) is cultivated for ornament. 
144. Corx L. 
Spikelets unisexual; staminate spikelets 2-flowered, in twos or 
threes on the continuous rachis, the normal group consisting of a pair 
of sessile spikelets with 
a single pedicellate 
spikelet between, the lat- 
ter sometimes reduced 
to a pedicel or wanting ; 
glumes membranaceous, 
obscurely nerved; 
lemma hyaline, nearly 
as long as the glumes, 
awnless, 5-nerved; palea 
hyaline, a little shorter 
than the lemma; sta- 
mens 3; pistillate spike- 
lets 3 together, 1 fertile 
and 2 sterile at the base 
of the inflorescence; fer- 
tile spikelet consisting 
of 2 glumes, 1 sterile 
lemma, a fertile lemma, 
and a palea; glumes sev- 
eral-nerved, hyaline be- 
low chartaceous in the 
upper narrow pointed Fic. 174.—Job’s-tears, Coix lachryma-jobit. Upper por- 
part, the first very ree 
broad, infolding the spikelet, the margins infolded beyond the 2 
lateral stronger pair of nerves, the second glume narrower than the 
first, keeled; sterile lemma about as long as the second glume, similar 
in shape but a little narrower, hyaline below, somewhat chartaceous 
above; fertile lemma hyaline, narrow, somewhat shorter than the 
sterile lemma; palea hyaline; narrow, shorter than the lemma; sterile 
spikelets consisting of a single narrow tubular glume as long as the 
fertile spikelet, somewhat chartaceous. 
'See Montgomery, The Corn Crops, 15, 1913: Sturtevant, U. 8S. Dept. Agr., Off. Wxp, 
Sta. Bull. 57. 1899. 
