Symphony parts

Usage examples of movements.

Distinction between heliotropism and the effects of light on the periodicity of the movements of leaves--Heliotropic movements of Beta, Solanum, Zea, and Avena--Heliotropic movements towards an obscure light in Apios, Brassica, Phalaris, Tropaeolum, and Cassia--Apheliotropic movements of tendrils of Bignonia--Of flowerpeduncles of Cyclamen--Burying of the pods--Heliotropism and apheliotropism modified forms of circumnutation--Steps by which one movement is converted into the other Transversalheliotropismus or diaheliotropism influenced by epinasty, the weight of the part and apogeotropism--Apogeotropism overcome during the middle of the day by diaheliotropism--Effects of the weight of the blades of cotyledons--So called diurnal sleep--Chlorophyll injured by intense light--movements to avoid intense light.

Any one who will consider this list will see that the young plants selected for observation, fairly represent the whole vegetable series excepting the lowest cryptogams, and the movements of some of the latter when mature will hereafter be described.

A filament with a bead at the end was affixed to the basal leg, the movements of which were observed during two days in the usual manner.

In order to ascertain more accurately the nature of these movements, the hypocotyl of a seedling, with its cotyledons well expanded, was secured to a little stick, and a filament with triangles of paper was affixed to one of the cotyledons.

All these observations are liable to several causes of error, but we believe, from what will hereafter be shown with respect to the movements of the radicles of other plants, that they may be largely trusted.

THE circumnutating movements of the several parts or organs of a considerable number of seedling plants have been described in the last chapter.

Preliminary sketch of the sleep or nyctitropic movements of leaves--Presence of pulvini--The lessening of radiation the final cause of nyctitropic movements--Manner of trying experiments on leaves of Oxalis, Arachis, Cassia, Melilotus, Lotus and Marsilea and on the cotyledons of Mimosa--Concluding remarks on radiation from leaves--Small differences in the conditions make a great difference in the result Description of the nyctitropic position and movements of the cotyledons of various plants--List of species--Concluding remarks--Independence of the nyctitropic movements of the leaves and cotyledons of the same species--Reasons for believing that the movements have been acquired for a special purpose.

But in a future chapter we shall have to recur to the movements of certain cotyledons which sleep at night.

In the following summer, the hypocotyl of a fourth seedling was secured to a little stick, and a glass filament with triangles of paper having been fixed to one of the cotyledons, its movements were traced on a vertical glass under a double skylight in the house.

In accordance with these conclusions, a considerable difficulty in the way of evolution is in part removed, for it might have been asked, how did all these diversified movements for the most different purposes first arise?

The movements of a young plant bearing a few leaves and of a mature plant, will hereafter be described.

In order to observe the movements of the epicotyl at a somewhat more advanced age, a filament was fixed near the base of one which was no longer arched, for its upper half now formed a right angle with the lower half.

With respect to the periodical movements of the cotyledons, those of several young seedlings formed together at 4 P.

Had the temperature been higher and the light brighter, the movements would probably have been greater.

The movements of the cotyledons are interesting from their complexity and rapidity, and in some other respects.