I have seen a sub-peduncle thickly
covered with flower-buds, with one of its higher lateral branchlets
bearing from some cause only two buds; and this one branchlet had
become much elongated and had spontaneously caught hold of an
adjoining twig; in fact, it formed a little sub-tendril. The
increasing length of the sub-peduncle (C) with the decreasing number
of the flower-buds is a good instance of the law of compensation. In
accordance with this same principle, the true tendril as a whole is
always longer than the flower-stalk; for instance, on the same plant,
the longest flower-stalk (measured from the base of the common
peduncle to the tip of the flower-tendril) was 8.5 inches in length,
whilst the longest tendril was nearly double this length, namely 16
inches.
The gradations from the ordinary state of a flower-stalk, as
represented in the drawing (fig. 10), to that of a true tendril (fig.
9) are complete. We have seen that the sub-peduncle (C), whilst
still bearing from thirty to forty flower-buds, sometimes becomes a
little elongated and partially assumes all the characters of the
corresponding branch of a true tendril. From this state we can trace
every stage till we come to a full-sized perfect tendril, bearing on
the branch which corresponds with the sub-peduncle one single flower-
bud! Hence there can be no doubt that the tendril is a modified
flower-peduncle.
Pages:
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184