160 PEOCEEDINGS OF THE AMERICAN ACADEMY 



lower glume becomes very hard and rigid, excepting its margin, and 

 fiimly embraces the lower part of the kernel. 



The ears upon the plants raised in the Botanic Garden were very 

 variable, from scarcely two inches to four inches in length and three 

 fourths of an inch broad, tapering slightly to an acuti^h apex, and 

 with the kernels in four, eight, ten, and sometimes twelve, but most 

 frequently in ten rows. A con)parison of these shows clearly the struc- 

 ture of the ear. When there are only four rows, the ear is flattened 

 and distichous, and the opposite pairs of rows are evidently the result 

 of the pairs of spikelets regularly alternating upon the opposite sides 

 of an extremely short-jointed and very flexuous rhachis. In the eight- 

 rowed ear the rhachis is four-sided instead of two-sided, and in the 

 ten-rowed it becomes five-sided. This latter case corresponds to the 

 arrangement in the terminal raceme of the staminate inflorescence, 

 where the spikelets are usually in five rairks. In the eight-rowed ear 

 each joint bears two opposite pairs of spikelets, alternating with those 

 of the joints immediately above and below, and in the twelve-rowed 

 there are three pairs to each joint, alternating in the same way. The 

 kernels are somewhat imbricated in the rows, and usually alternat- 

 ing, owing to one of the spikelets in each pair being slightly pedicel- 

 late. They are small, ovate, somewhat flattened dorsally and pointed, 

 the lower part constricted by the closely embracing glume. In struc- 

 ture they are hard and corneous, with a central starchy layer extend- 

 ing from the base nearly to the apex. The ripened ear breaks readily 

 at any point, so that the eight-rowed ear, for example, may be separated 

 into its several joints, each bearing two opposite pairs of kernels. I 

 would therefore characterize the new species as follows: — 



Z. CANINA. Culms several from the same root, ascending, branched : 

 staminate racemes often elongated and drooping ; spikelets 2 to 4 (usu- 

 ally 3) at each node, one or more short-pedicelled ; empty glumes 3- 

 5-nerved, bicarinate : pistillate spikes sessile in the axils and terminal, 

 the terminal staminate at the apex; ears small, 4-12-rowed, dividing 

 more or less readily at the joints ; kernels small (3 to 4 lines long), 

 white, hard and smooth, ovate, acutish, constricted at base. 



The location from which the specimens were obt.iincd for Prof. 

 Duges is stated more definitely to be IMoro Leon (otherwise Congre- 

 gacion), near Uriangato, about four Mexican leagues nortli of T^ake 

 Cuitzco. It is therefore near the boundary line betweiMi the States 

 of (juanajuato and INIichoacan. The natives of the district are said 

 by I'rof. Duges to believe the mn'/'s (J" cnyofe to be the source of the 

 cultivated varieties of maize, notwithstanding the recognized dill'er- 



