apheliotropism

Apheliotropism, or, as usually designated, negative * 'Physiologie Veg.'

But from observing the effects of placing plants in the dark, in which case several shoots became in two or three days upright or nearly upright, and when brought back into the light again became rectangularly curved, we believe that the bending is in part due to apheliotropism, apparently somewhat opposed by apogeotropism.

Whether the exciting cause of the downward movement is geotropism or apheliotropism was not ascertained; but probably it is not apheliotropism, as all the gynophores grew straight down towards the ground, whilst the light in the hot-house entered from one side as well as from above.

Apheliotropism.—We succeeded in observing only two cases of apheliotropism, for these are somewhat rare; and the movements are generally so slow that they would have been very troublesome to trace.

Many organs bend downwards through epinasty or apheliotropism or from their own weight; but we have met with very few cases of a downward movement in sub-aërial organs due to geotropism.