HooKkER: PHYSIOLOGICAL OBSERVATIONS 
ing was a nutation or a variation movement. Analogy with the 
behavior of tendrils, which has been thoroughly investigated by 
Fitting, indicates that the reactions of Drosera are phenomena of 
growth, and this is substantiated by Ba‘asin’s (’77, p. 36) some- 
what meager measurements. These are, in Pfeffer’s words (’06, 
3: 85), ‘‘not fully satisfactory.’’ Although the primary pur- 
pose of this paper is to settle this point, a number of observa- 
tions were made during the work which pertain to other matters. 
These minor points are of some physiological interest and will be 
mentioned before proceeding to the main discussion. 
2. MATERIAL 
The material used was collected during the months of July 
and August from Beaver Swamp in the city of New Haven, ~ 
Connecticut. It was found advisable to use only fresh material 
for experimentation. 
Plants of Drosera rotundifolia and D. longifolia were found 
growing in Sphagnum. In removing them, large pieces of the 
substratum were taken along with the plants to prevent injury 
to the roots and to insure their further development in the labora- 
tory. Slight injuries to the roots cause the secretion of the glands 
to stop and render the tentacles inactive, so that they fail to 
respond to the customary stimuli. The root-hairs are particu- 
larly remarkable, for they are not restricted to a small region 
above the root-tip but cover the entire length of the root. They 
do not die, but continue to grow and function. In this way they 
increase the effectiveness of the small root-system. 
The plants were placed in flat dishes, made wet with distilled 
water and covered with bell-jars. Under these conditions the 
development of the plants was far from normal. The rosette 
arrangement of the leaves was lost, a typical stem was developed 
by lengthening of the internodes and every trace of red pigment 
disappeared. No gradations from purple to green leaves were 
observed. All the leaves, which unfolded in the moist atmosphere 
and subdued light of the culture, were green. The size of the 
leaves diminished and their petioles made a more acute angle 
with the stem, causing them to point obliquely upward instead 
of horizontally outward. 
