Vlii CONTENTS. 



night — Averrhoa: rapid movements of the leaflets — PorlieriR; 

 leaflets close when plant kept very dry — Tropa?olum : leaves do 

 not sleeji unless -well illuminated during day — Lupinus : various 

 modes of sleeping — Mehlotus: singular movements of terminal 

 leaflet — Trifolium — Desmodium : rudimentary lateral leaflets, 

 movements of, not developed on yonng plants, state of their 

 pulvini — Cassia : complex movements of the leaflets — Bauhinia: 

 leaves folded at ni^ht — Mimosa pudica: compounded move- 

 ments of leaves, cifect of darkness — Mimosa albida, reduced 

 leaflets of — Schrankia : downward movement of the pinnje — 

 Marsilea: the only cryptogam known to sleep — Concluding 

 remarks and summary — Xyctitropism consists of modified cir- 

 oumnutation, regulated by the alternations of light and darkness 

 ^Shape of first true leaves Page 317-417 



CHAPTEE Vlir. 



Modified Cibcumxutation : Movements excited by Liqht. 



Distinction between heliotropism and tlie effects of light on the 

 periodicity of the movements of leaves — Heliotropic movements 

 of Beta, Solanum, Zea, and Avena — Heliotiopio movements 

 towards an obscure light in Apios, Brassica, Phalaris, Tropieo- 

 lum, and Cassia — Apheliotropio movements of tendrils of Big- 

 nonia — Of flower-peduncles of Cyclamen — Burying of the pods 

 — Heliotropism and apheliotropism modified forms of circumnu- 

 tation — Steps by which one movement is converted into the 

 other — Transversal-heliotropismus or diaheliotropism influenced 

 by epinasty, the weight of the part and apogeotropism — Apogeo- 

 tropism overcome during the middle of the day by diaheliotro- 

 pism — Effects of the weight of the blades of cotyledons — So- 

 called diurnal sleep — ChlofO])hyll injured by intense light — 

 Movements to avoid intense light 418-448 



CHAPTEE IX. 



Sensitivfness of Plants to Light : its transmitted ErrBOTa. 



Uses of he'iotropism— Insectivorous and climbing plants not hello- 

 tropic — Same organ heliotropic at one age and not at another— 

 Extraordinary sensitiveness of some plants to light — The effbcts 



