[27]

[Letter not transcribed]

[27v]

either to the left or, the right, until its upper surface comes into contact with that of the lateral leaflet on the same side, which has likewise rotated on its own axis.

With arachis all four leaflets form together during the night a single vertical packet; & the effect thus the two anterior leaflets have to move backwards & the two posterior ones forward, besides all leaning twisting on their own axes. In the genus Sida the leaves of some species move at night through an angle of 90˚ upwards, & of others through the same angle downwards.

We have seen a like difference in the nyctitropic movements of

[Movement in plants, pp. 394-5: "The terminal leaflet of Melilotus likewise rotates, by which movement one of its lateral edges is directed upwards, and at the same time it moves either to the left or to the right, until its upper surface comes into contact with that of the lateral leaflet on the same side, which has likewise rotated on its own axis. With Arachis, all four leaflets form together during the night a single vertical packet; and to the effect this the two anterior leaflets have to move upwards and the two posterior ones forwards, besides all twisting on their own axes. In the genus Sida the leaves of some species move at night through an angle of 90° upwards, and of others through the same angle downwards. We have seen a similar difference in the nyctitropic movements of the cotyledons in the genus Oxalis."]