93 



a maximum rate of growth. In this case it occurs at the time when the 

 shoot has just appeared above the water. The highest number got for the 

 daily growth was 26 cm., which was observed in leaf-stalk, IV, 



After this maximum was attained the daily growth becomes less day 

 by day, until it ceases. In the leaf-stalk the maximum growth occurs 

 before - the unfolding of the leaf, and its growth continues after the leaf 

 has fully developed and acquired vigorous power of assimilation. As we 

 can see in tables I — VII, the maximum growth of the leaf is a little 

 later than that of the leaf-stalk. It occurs just at the time of the leaf's 

 unfolding. The same was observed by Caspary n in the growing leaf of 

 Victoria regia. He found that the growth is most vigorous on the day 

 of its unfolding. 



The rate and mode of growth of the flower-stalk does not differ from 

 that of the leaf-stalk. The daily maximum growth given in flower-stalks, I 

 and III is a little less than that of the leaf-stalk, but such is not always 

 the case. As I have already said, my observations began a little after 

 the maximum was attained, and therefore the daily maximum growth 

 given in these tables is not the maximum of the whole course of growth, 

 but of that within the limit of my observations. After the maximum is 

 attained the flower-stalk continues to grow till the bud developes and 

 uncloses to become the large and beautiful flower. 



These data can be also expressed by the curve which is given in PI. 

 IV. The curves of daily changes of temperature are also shown there. 

 We can see from it that the grand period (grosse Periode) 2) of growth is 

 independent, within certain limits, of changes of temperature. 



As I could not measure the growth under the water the whole curve 

 of growth is incomplete. The greater part of the ascendiug curve would 

 have to be obtained from measurements under the water. After the 

 top of the curve is reached its descending slope runs smoothly with 

 none of the zigzag or undulation, which is observed in the case of 

 many other plants and called by Sachs " stossweise Aenderuugen des 

 Wachsthums." 3) 



1) Caspary, fiber das tiigliche Wachsthuni des Blattes der Victoria regia und des Pflanzen- 

 wachsthums iiberhaupt. Flora 1856. 



2) Sachs, Ueber den Einfluss der Luftteniperatur und des Tageslichts auf die stiindlichen 

 und taglichen Aenderungen des Lagenwachsthums der Internodien. Arbeit, des bot. Inst, zu 

 Wiirzburg, Bd. I, Heft 2, 1872, P. 102. 



3) Sachs, 1. c, p. 103. 



