The
cotyledons of another seedling, which when first observed had already
produced a leaf, stood vertically at night and continued to do so for 11
additional days. After 16 days from the first observation two leaves were
developed, and the cotyledons were still greatly raised at night. After 21
days the cotyledons during the day were deflected beneath the horizon, but
at night were raised 45o
[page 116]
above it. After 24 days from the first observation (begun after a true leaf
had been developed) the cotyledons ceased to rise at night.
Oxalis (Biophytum) sensitiva.--The cotyledons of several seedlings, 45 days
after their first expansion, stood nearly vertical at night, and closely
embraced either one or two true leaves which by this time had been formed.
These seedlings had been kept in a very warm house, and their development
had been rapid.
Oxalis corniculata.--The cotyledons do not stand vertical at night, but
generally rise to an angle of about 45o above the horizon. They continued
thus to act for 23 days after their first expansion, by which time two
leaves had been formed; even after 29 days they still rose moderately above
their horizontal or downwardly deflected diurnal position.
Pages:
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207