226 CIRCUMNUTATION OF LEAVES. CHAP. IV. 



of many plants, for instance, those of Brassica napus, revolve or 

 circutn nutate; those of Alliam porrum bend from side to side, 

 aud, if this movement had been traced on a horizontal glass, 

 no doubt ellipses would have been formed. Fritz Miiller has 

 described * the spontaneous revolving movements of the flower- 

 stems of an Alisma, which he compares with those of a climbing 

 plant. 



We made no observations on the movements of the different 

 parts of flowers. Morren, however, has observed f in the 

 stamens of Sparmannia and Cereus a " fren Jsseaient spontane," 

 which, it may be suspected, is a circumnutating movement. 

 The circumnutation of the gynostemium of Stylidium, as de- 

 scribed by Gad,J is highly remarkable, and apparently aids in 

 the fertilisation of the flowers. The gynostemium, whilst spon- 

 taneously moving, comes into contact with the viscid labellum, 

 to which it adheres, until freed by the increasing tension of the 

 parts or by being touched. 



We have now seen that the flower-stems of plants 

 belonging to such widely different families as the 

 Cruciferae, Oxalidse, Leguminoste, Primulacere, Scro- 

 phularineae, Alismaceae, and Liliacefe, circumnutate ; 

 and that there are indications of this movement in 

 many other families. With these facts before us, 

 bearing also in mind that the tendrils of not a few 

 plants consist of modified peduncles, we may admit 

 without much doubt that all growing flower-stems 

 circumnutate. 



CIRCUMNUTATIOX OP LEAVES : DICOTYLEDONS. 



Several distinguished botanists, Hofmeister, Sachs, 

 Pfeffer, De Vries, Batalin, Millardet, &c., have ob- 



p. 766. Lmnrens and Trevintnus plies drcumnutation. 



(according to Pfeffer, 'Die Pe- * 'Jenaische Zeitsch.,' B. T. 



riodischen Bewegungen,' &c., p. p. 133. 



162) stato that the flower-stalks f ' N". Mem. de 1'Acad. R. da 



of many plants occupy different Bruxelles,' torn. xiv. 1841. p. 5$. 



positions by night and day, and J ' Sitzungbericht des hot. Ve- 



we shall see in the chapter on reiis der P. Brandenburg,' xxi 



the Sleep of Plants that this im- p. 84. 



