Zeitung,' 1866,
pp. 57, 66.
{21} It appears from A. Kerner's interesting observations, that the
flower-peduncles of a large number of plants are irritable, and bend
when they are rubbed or shaken: Die Schutzmittel des Pollens, 1873,
p. 34.
{22} I have already referred to the case of the twining stem of
Cuscuta, which, according to H. de Vries (ibid. p. 322) is sensitive
to a touch like a tendril.
{23} Dr. Maxwell Masters informs me that in almost all petioles
which are cylindrical, such as those bearing peltate leaves, the
woody vessels form a closed ring; semilunar bands of vessels being
confined to petioles which are channelled along their upper surfaces.
In accordance with this statement, it may be observed that the
enlarged and clasped petiole of the Solanum, with its closed ring of
woody vessels, has become more cylindrical than it was in its
original unclasped condition.
{24} Never having had the opportunity of examining tendrils produced
by the modification of branches, I spoke doubtfully about them in
this essay when originally published. But since then Fritz Muller
has described (Journal of Linn. Soc. vol. ix. p. 344) many striking
cases in South Brazil.
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