60 Waight,—On the Presentation Time and Latent Time for 
As 'previously described, 1 the frond of Asplemum bulbiferum passes 
through a grand period of growth whose maximum under favourable con¬ 
ditions is i-i* 8 cm. a day at adolescent stages. 2 The increments are shown 
separately in the graph as ordinates corresponding with the same stages 
76 -1 
of frond development. This brings out the fact that though response 
to gravity ceases while the frond is still growing, the presentation time is 
least when growth is most rapid. Thus maximum growth is associated 
with minimum presentation time, and hence with maximum geotropic 
irritability, in so far as the one is a true measure of the other. 
1 Prankerd: loc. cit., p. 144. 
2 One cm. is also approximately the interval between each pair of leaflets at the time of their 
unfolding, hence about one pair a day are produced at I5°-20°C. 
Inc^emenp6 of Qrowt-h. 
irx nvll i metre*. 
