14 GRASSES OF IOWA. 



The iallest were over ten feet high, with a diameter of nearly two 

 inches, and they would have become yet taller had the season permitted. 

 Their foliage and pubescence were in every way as in ordinary field corn, 

 the staminate tassels with conspicuously longer and more drooping 

 racemes, the habit of growth wholly unusual. In our ordinary form 

 the erect culm is always apparently single, bearing solitary axillary 

 ears which terminate a usually short leafy-bracted peduncle. This 

 peduncle is in fact a lateral branch, bearing a terminal pistillate 

 spike corresponding to the staminate panicle on the main stem. In this 

 Mexican corn, on the other hand, the better developed stalks were evi- 

 dently branched from several of the axils, the branches often becoming 

 three or four feet in length, very leafy, and having at least a rudimen- 

 tary ear in the axil of every leaf. Several, sometimes half a dozen, per- 

 fect ears were formed upon each branch. The terminal ear was always 

 androgynous, staminate at the summit. On the shorter stems the 

 branches were reduced to a more or less crowded axillary cluster of ears 

 similar to the one received from Professor Duges. The last year's sea- 

 son was a long one, and there was no heavy frost in Cambridge until 

 near the end of October. The corn, however, was at that time still 

 very green, and the stalks were finally cut and stored under shelter in 

 the hope that the ears would ripen in the stack ; but upon very few did 

 any of the kernels mature. 



"The natural supposition was that we had here at least the original 

 wild state of our cutivated maize. A careful comparison of the two, as 

 thorough as the material at hand of the cultivated forms would permit, 

 has led me first to doubt the probability of this, and now to consider the 

 form in question a distinct species. The differences upon which this con- 

 clusion is based are in the habit of growth, the arrangement of the stam- 

 inate spikelets, and the nervation of their glumes, the form of the glumes 

 of the pistillate flowers, and the ready disarticulation of the ripened ear. 



'It appears from descriptions, figures, and such specimens as I have 

 seen of cultivated maize, that the staminate spikelets are in pairs at the 

 joints of the rachis, and their empty glumes 7-9 nerved. In the Mexi- 

 can plant there are usually three and sometimes four together, one 'of 

 them short-pedicelled, the others more nearly sessile. The empty glumes 

 are 3-5 nerved and bicannate, the flowering ones more narrow than in 

 Zea Mays. The pistillate spikelets are in pairs at the joints of the 

 rachis, the internodes of which are more or less strongly margined and 

 cupulate, and finally become hard and shining. The glumes are very 

 broad, strongly concave and enfold each other much more than in the 

 flowers, of Zea Mays that I have examined, and more than they are rep- 



