1920] 



WE A THERWAX— MAIZE 



181 



that may be called a cotyledon is visible (fig. 1), the whole structure 



due to the more rapid development 



mmetrical form 



em 



laterally of the cotyledon, and sul 

 (figs. 2-7). That the coleoptile is at first directed horizontally or 

 downward, as is emphasized by Worsdell, is of little significance; 

 morphological position cannot always be determined geometrically. 

 Moreover, Worsdell's 3 figures, taken from another authority in 



1 



9 



Figs. 8-1 i. — Figs. 8, 9, transverse sections of embryo through plumule: VS, vas- 

 cular strands of scutellum; VC, vascular strands of coleoptile; L y foliage leaf; C, point 

 of union between two sides of coleoptile, forming closed sheath; sections of embryo 

 of liguleless variety in no essential way different from these; X15; fig. 10, germi- 



nating seed of liguleless maize: coleoptile present and normal; fig. 11, seedling of 

 maize, showing forked coleoptile. 



substantiation of his position, are only the upper parts of embryos; 

 if we attach to the figures the lower parts of the corresponding stages 

 of development of the embryo of any typical grass, the continuity 

 of cotyledon, hypocotyl; and suspensor as the axis of the embryo 

 is evident. 



The second point in support of the view taken by Coulter and 

 Land is afforded by the embryo of a liguleless variety of maize 

 isolated by Emerson a few years ago. These plants are like those 

 of ordinary maize, except that they breed true for the absence of 



'Ibid., fig. 3 ,A-E, p. 511. 



