ERRATUM.
At page 59 I have said that there are only three or four species of Mimosa which are sensitive. This is a mistake, as the greater portion of the species in the extensive genus Mimosa, as well as some species of several other genera of Leguminosæ, and also of Oxalidaceæ, possess this curious property. I cannot find, however, that any one has suggested in what way the sensitiveness may have been useful to the species which first acquired it. My guess at an explanation may therefore induce botanists who are acquainted with the various species in a state of nature, to suggest some better solution of the problem.