. Xmphicarpcea tnonoica. 



Judging only from what has been learned of one plant, I 

 conclude that in addition to height of specimen, information 

 concerning temperature, conditions of moisture, exact time 

 of day at which the experiment was made-, and also light 

 intensity should be stated. 



A few items of detail may not be out of place here. 

 Amphicarpoea positively refused to cirenmnntate if exposed 

 to a temperature of 15° C. for any length of time. If re- 

 tained at such a temperature for a day or two, the effects of 

 the injurious environment remained for some hours after 

 the plant was placed under more favorable conditions. 



( )n the other hand, a temperature of 38 C. or over seemed 

 to have a similar paralyzing effect. If supported, the plant 

 remained almost stationary, and often drooped. If free, the 

 movements were irregular and spasmodic, partly due to the 

 plant's adjusting its equilibrium, which is more or less dis- 

 turbed by the para-heliotropic position of the leaves. Upon 

 one occasion, a plant behaved as above indicated, tempera- 

 ture 40 C. ; it was carried into a cooler greenhouse, the 

 temperature there being 24 C. Apparently undisturbed 

 by being moved, in a few moments the plant recovered 

 from the heat, and proceeded in its usual circular path. 



Many of the diagrams given by various authors to illus- 

 trate circumnutation, indicate that an erratic or sometimes 

 a sinuous course, has been taken by the plant. It is pos- 

 sible that these results are due to a temperature which is 

 too high for the species. The exceedingly long time 

 required by certain plants may partly be caused by an in- 

 juriously low temperature. 



The 'most favorable temperature for Amphicarpaa is 

 from 26 to 32 C. ; good results are obtained with the 

 thermometer above and below these figures, but the most 

 rapid circumnutation usually occurs within these limits. 



If a plant is taken from the moist greenhouse and placed 

 in a dry room, marked retarding of movement occurs, 

 though the temperature is about the same. 



Placing a lighted lamp or candle during night, before a 



