CHAPTER VII.

Modified circumnutation:  Nyctitropic or sleep movements of leaves.

Conditions necessary for these movements—­List of Genera and Families, which include sleeping plants—­Description of the movements in the several Genera—­Oxalis:  leaflets folded at [page viii.] night—­Averrhoa:  rapid movements of the leaflets—­Porlieria:  leaflets close when plant kept very dry—­Tropaeolum:  leaves do not sleep unless well illuminated during day—­Lupinus:  various modes of sleeping—­Melilotus:  singular movements of terminal leaflet—­Trifolium—­Desmodium:  rudimentary lateral leaflets, movements of, not developed on young plants, state of their pulvini—­Cassia:  complex movements of the leaflets—­Bauhinia:  leaves folded at night—­Mimosa pudica:  compounded movements of leaves, effect of darkness—­Mimosa albida, reduced leaflets of—­Schrankia:  downward movement of the pinnae—­Marsilea:  the only cryptogam known to sleep—­Concluding remarks and summary—­Nyctitropism consists of modified circumnutation, regulated by the alternations of light and darkness—­Shape of first true leaves...Page 317-417

CHAPTER VIII.

Modified circumnutation:  Movements excited by light.

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 flower-peduncles of Cyclamen—­Burying of the pods—­Heliotropism and apheliotropism modified forms of circumnutation—­ Steps by which one movement is converted into the other—­ Transversal-heliotropismus 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...418-448

CHAPTER IX.

Sensitiveness of plants to light:  Its transmitted effects.

Uses of heliotropism—­Insectivorous and climbing plants not heliotropic—­ Same organ heliotropic at one age and not at another—­Extraordinary sensitiveness of some plants to light—­The effects [page ix.] of light do not correspond with its intensity—­Effects of previous illumination—­Time required for the action of light—­After-effects of light—­Apogeotropism acts as soon as light fails—­Accuracy with which plants bend to the light—­This dependent on the illumination of one whole side of the part—­Localised sensitiveness to light and its transmitted effects—­Cotyledons