182 BOTANICAL GAZETTE [February 



ligules and auricles. A few of the plants tend to produce at least 

 rudimentary ligules on the uppermost leaves, but they are regu- 

 larly absent from the lower leaves, and the condition might reason- 

 ably be expected to extend to the cotyledon also. An examination 

 of the embryo and of the seedling, however, shows the coleoptile 

 to be present and normally developed (figs. 8-10). While this fact 

 cannot be accepted as a proof of anything, it should at least not be 



overlooked in considering the question. 



em 



ment 



this 



It is true that 



the coleoptile has two vascular strands bilaterally placed (figs. 8, 9), 

 while the foliage leaf has several strands equally distributed; but 

 this modification in vascular anatomy is no more significant than 



scutellum (fizs. 8. o). in a Dronhvllum. or in 



many 



ments present in two groups, and yet all of which 



modified foliage leaves. The forked col eon tile is a 



common 



having 



number of seedlings of maize, 



conditions. The coleoptile begins to develop as an open sheath 



form 



j 



but the line of this union is always visible (figs. 8, 9), especially 

 near the top of the sheath. Too much significance must not be 

 attached to the nature of the mechanical rupture of this structure 

 by the elongating plumule. If the union of the two sides has not 

 been very firm, and it usually is not, the structure will split on one 

 side only; but if the two sides are firmly grown together, the coleop- 

 tile may split for a short distance down two sides, producing the 

 forked coleoptile (fig. 11). The relation between this occurrence 

 and the duplex ligules of some grasses, or the two stipules of some 

 other plants, is too remote to merit consideration. 



It may be said, therefore, that the evidences derived from the 



the liguleless mutant, favor the 

 logue of a foliage leaf, and thai 



Indiana University 

 Bloomington, Ind. 



mbry 



