June i6, 1919 



Structure of Maize Ear 



129 



sessile spikelets, the two sessile spikelets would stand next each other 

 as would the two pedicelled spikelets (see fig. i, A). This lack of 

 radial symmetry will be shown to be a very persistent and important 

 feature. 



Fig. I. — Diagram showing arrangement of pedicelled and sessile spikelets in A, undifferentiated four-rowed 

 branch; E, eight-rowed ear, the result of the fasciation of two tmdifferentiated branches; C, eight-rowed 

 ear the result of twisting a single undifferentiated branch; D, i6-rowed ear, the result of fasciation; 

 E, i6-rowed ear, the result of a further twisting of "C." 



Turning now to the pistillate inflorescences a striking contrast appears. 

 Both spikelets are sessile in Zea, and it is usually impossible to deter- 

 mine which of the pair is the homologue of the pedicelled spikelet. In 

 the pistillate inflorescence of Huchlaena, the spikelets are borne singly 

 instead of being paired. It is the pedicelled spikelet that is suppressed, 

 as is clearly shown in the hybrid plants where all stages of suppression 

 can be observed (PI. 17, A). I<'urthermore, in pure Euchlaena starainate 

 branches frequently have pistillate spikelets at the base. In such speci- 

 mens at the place v^^here the transition occurs, rudiments of a pedicelled 

 staminate spikelet can often be seen by the side of a sessile spikelet 

 bearing a well-developed seed. 



