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In three cases alone the radicles were not affected by the
difference in thickness of the squares of paper attached to their tips, and
consequently did not bend away from the side bearing the stiffer paper.
Zea mays: Sensitiveness of the apex of the Radicle to contact.--A large
number of trials were made on this plant, as it was the only monocotyledon
on which we experimented. An abstract of the results will suffice. In the
first place, 22 germinating seeds were pinned to cork-lids without any
object being attached to their radicles, some being exposed to a
temperature of 65o - 66o F., and others to between 74o and 79o; and none of
them became curved, though some were a little inclined to one side. A few
were selected, which from having germinated on sand were crooked, but when
suspended in damp air the terminal part grew straight downwards. This fact
having been ascertained, little squares of the card-like paper were affixed
with shellac, on several occasions, to the tips of 68 radicles. Of these
the terminal growing part of 39 became within 24 h.


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