roS 



MAIZE 



CHAP. 

 IV. 



Protainiry is the opposite of protogyny, i.e. the anthers 

 shed all or part of their pollen before the female organs of the 

 same plant are receptive. The very earliest pollen shed will, 

 in such a case, be entirely wasted unless there is a protogyn- 

 ous plant in the vicinity which is receptive at the same time. 



Plants of Black Sugar-maize in Pretoria, which matured 

 pollen on 14 December, 1907, did not have any receptive stig- 

 mas till the 1 6th, 17th, and even later. In some instances 

 the tassels had shed all their pollen before any silk appeared. 



As far as the writer has been able to determine, from 

 observation of Transvaal maize fields, protandry is the rule 

 in South African maize. And Shamel (1) states that in 

 America " in most varieties the pollen matures before the 

 silks". On this account well-filled butts are more frequent 

 than well-filled tips. 



At the Botanical Experiment Station, Pretoria, no case of 

 protogyny was observed among seventeen plants under obser- 

 vation for time of relative maturity of pollen and silk. 



In another experiment, however, with another variety of 

 maize (a yellow flint, Wills Genu), even- one of twenty-six 

 plants under observation was protogynous. 



Plants of Arcadia Sugar-maize which developed silks on 

 9 November, 1910, had no anthers exserted until the 11th, 

 while others had no anthers till the 1 3th. In some cases the 

 tassels appear long before the anthers ; the writer has a note of 

 one vigorous plant of Louisiana Hickory on which the tassel 

 first appeared on 25 November, but there were no anthers 

 until 8 December, i.e. thirteen days later, the silks appearing 

 on the same day. 



It seems probable that protogyny is a breed characteristic. 

 It appears to be constant in Arcadia Sugar-maize and in 

 Wills Gehu (yellow flint), while protandry is the rule in 



