68 Stmons— Comparative Studies on the Rate of 
Later in the season, on July 18, August 8 and 15, experi- 
ments were performed on shoots of Convolvulus Sepium grow- 
ing inthe garden. The plant spread itself, for the most part, 
along the ground, slender branches, now and then, standing 
upright and exhibiting a tendency to climb. The times of 
revolution were as shown in the table appended, the shortest, 
1 hour 11 minutes, being longer than the spring time of 57 
minutes. This plant produces two distinct types of stem, the 
twining and the prostrate. The latter are of a darker color, 
more woody, thicker and have stronger tips. Two of these 
were tied to a support and watched from 8.30 till 1. There 
was no perceptible movement, later a slight one. Nothing 
further took place before 2.35 p. m., when observation ceased. 
Three days later no evidence of ability to climb could be 
noticed, the stems having been left tied to their supports. 
Humulus Lupulus.—Winter buds of the Hop were trans- 
planted and formed vigorous shoots by February 9, when 
circumnutation movements were observed during two days 
(two distinct plants used), with the appended results. 
The periodicity of growth was not so marked in this case, 
but gave indication of afternoon acceleration, as will be seen 
by reference to the table. 
Darwin’s shortest time for the Hop was 2 hours 8 min- 
utes, during what he called ‘hot weather.’’ Our plants were 
first observed in late winter when 1 hour 5 minutes was 
the shortest period. On a hot day (July 15) tips of a 
plant growing in the garden were protected from wind, sup- 
ported, and watched under glass; the time 1 hour 40 min- 
utes, was obtained. Another tip made a circle in 2 hours 
35 minutes, when it seemed to be burnt. On August 16, 
another tip was tried, with the result 2 hours 14 minutes. 
Casually observed, the tips do not seem inclined to grow vig- 
orously in the hot weather. The quick spring movements 
confirm this. 
Loncera brachypodaand Phaseolus vulgaris were used in class 
