Altogether 153 genera, included in as
many families as could be procured, were thus observed by us. The
cotyledons were looked at in the middle of the day and again at night; and
those were noted as sleeping which stood either vertically or at an angle
of at least 60o above or beneath the horizon. Of such genera there were 26;
and in 21 of them the cotyledons of some of the species rose, and in only 6
sank at night; and some of these latter cases are rather doubtful from
causes to be explained in the chapter on the sleep of cotyledons. When
[page 112]
cotyledons which at noon were nearly horizontal, stood at night at more
than 20o and less than 60o above the horizon, they were recorded as
"plainly raised;" and of such genera there were 38. We did not meet with
any distinct instances of cotyledons periodically sinking only a few
degrees at night, although no doubt such occur. We have now accounted for
64 genera out of the 153, and there remain 89 in which the cotyledons did
not change their position at night by as much as 20o--that is, in a
conspicuous manner which could easily be detected by the unaided eye and by
memory; but it must not be inferred from this statement that these
cotyledons did not move at all, for in several cases a rise of a few
degrees was recorded, when they were carefully observed.
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