as 
4 
" 
< 
q 
z 
3 
a 
4 
q 
y 
1909] STREETER—DIRECTION OF GROWTH OF AMANITA 423 
growth ceases, the zone of elongation becomes shorter and shorter, 
but is always just below the pileus. In the specimens used to make 
out the above table, the length of the mature stipe varied from 36 
to 112™™, and the length of the zone of elongation varied from 2 
70.407, 
Record was made of the amount of elongation which had taken 
place in each part of the stipe beginning at the pileus. By referring 
to the table it can be seen that in those plants which are about one- 
third grown or less, the zone of most rapid elongation is in about the 
middle of the stipe. As growth continues, this zone moves up the 
stipe. In plants which are half grown or larger, the zone of most 
vigorous growth is the second 2™™ from the tip. When the zone of 
elongation becomes less than 4™ in length, growth takes place in the 
upper 2™™ (see record for 123). The elongation within the upper 
2™™ of the stipe is usually less than that within the second 2™™, but 
in some cases they are equal. The amount of elongation in each 
2™™ becomes less and less from the point of most rapid growth 
toward the base, until the growing region is passed. : 
In order to determine the time element in the geotropic response 
of these toadstools, plants were placed in a horizontal position in the . 
dark and records of the amount of curvature were taken each hour. 
The following table gives the records of two of these specimens: 
No. 51 No. 56 
Time igo Pe of Amount of 
an change ses change 
Position foreach Position tc back 
successive hour successive hour 
nh: Se SRA eae eer. °° or 
BAO A Me. cc ain s —4° —4° "a 5° 
RESO A. Meee cee ee ee =" Ss? og ic” 
BAS Ming coe ec ewe te ts 5 4° ar ee 
MAGA Moo vise cee he ee 8° 4° 32° 9° 
Wao Mok se tee ee tr” = 42° 10° 
EW sk ld woes ee re 4° 52 10° 
00 SG ESSE aia ar rrae ar rar| 19° 4° 62° 10° 
ee Pe ee ee ce 22° is 2° 10° 
3 3 
ee POM ees es eS 24 2° 82° 10° 
Be eM ha hee oss Ace 20° 2° 88° 6° 
See PMA op eee 28° 2° 92° 4° 
es Mile = vain gees 30° 2° 95° ss 
a errr | 32° 2 97° 2 
ee Ms ea is as 32° 0° + 98? ig 
Be A, Wee i Sa eee ws 32° 0° 98° 0° 
