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 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. 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.