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Research Bulletin A <>. i 
and 1128) were wholly protandrous. Some plants of the 1910 
F 2 lot I family 510) were observed to be protogynous but no 
adequate records were made of that family. Only one F 3 family 
(1132) contained protogynous plants. Of this family twenty 
eight plants were protandrous and only twelve protogynous. 
Of the latter the silks began to show from one to three days and 
on the average about two days earlier than the pollen began to 
shed. 
Had the time of exposure of the first silks instead of the time 
of shedding of pollen been taken as the date of flowering for all 
of the families, family 1132 would have been classed as even 
earlier and all the other F 3 families somewhat later than they 
were, for in protandrous corn the silks usually appear from one 
to four or five days after the pollen begins to shed. If protandry 
is regarded as the normal condition, because it is the most 
common, protogyny may be thought of as delayed development 
of the staminate flowers, in which case the time of exposure of 
the silks would better be used as the date of flowering, or it may 
be thought of as precocious development of the pistillate flowers, 
in which case the time of opening of the anthers would better be 
taken as the blossoming date. Or in case protogyny is considered 
normal and protandry abnormal, the latter may be regarded as 
delayed development of the pistillate flowers or as the precocious 
development of the staminate flowers. In the first case the silks 
and in the second the anthers would be the better index of flower 
ing. The fact that in protogynous types of corn, so far as they 
are known to us, the silks protrude from the leaf sheath before 1 
the ear-bearing shoot has appeared may perhaps be rightly re- 
garded as an indication of precocious development of the pistil 
late flowers. This would place protogyny as an "abnormal'' 
character and make the staminate flowers the better guide in 
fixing the date of flowering. It is probable, however, that both 
protogyny and protandry are quite normal. 
No attempt has been made as yet to study the inheritance of 
protogyny or protandry as definite characters. It is possible 
that they are mere chance relations between times of maturity 
of pistillate and staminate flowers. If so, however, there must 
be a pronounced physiological correlation between time of matur- 
ing of the two sorts of flowers, for otherwise any lot of corn with 
a considerable range of variation in time of flowering would by 
chance show all gradations from strong protandry to strong pro- 
togyny with slight protandry or protogyny or even homogamy as 
the modal condition. It is also likely that there is genetic corre- 
lation between the time of maturity of the staminate and pistil- 
late flowers and that this is in fact the only basis for considering 
protogyny and protandry as definite characters. If there were 
