226 CIKCUMNUTATION OP LEAVES. Chap. IV. 



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

 circumnutate ; those of Alliam porrum bend from side to side, 

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

 no doubt ellipses would have been formed. Fritz Muller has 

 described * the spontaneous revolving movements of the Bower- 

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

 plant. 



We made no observations on the movements of the different 

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

 stamens of Sparmannia and Cereus a " fren.issement spontane," 

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

 The circumnutation .of the gynostemium of Stylidium, as de- 

 scribed by Gad.t 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 

 Criiciferse, Oxalidse, Leguminosae, PrimulacesB, Scro- 

 phularineae, Alismaeea3, and Liliacese, 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. 



Circumnutation of Leaves : Dicotyledons. 



Several distinguished botanists, Hofmeister, Sachs, 

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



p. 766. Lmnneus and Trevinmus plies ciicumnutation. 



(nocoiding to Pfeffer, ' Die Pe- * ' Jenaisohe Zeitsch.,' B. v. 



riodischeii Bewegungen,' &o., p. p. 133. 



162) fctato tliat tlie flower-stalks f 'N. Mem. de I'Acad. E. de 



of many plants occupy different BruxeUr-s,' torn. xiv. 1841, p. 3. 



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



we shall S' e in the chapter on reins d'.T P. Brandenburg,' ixi 



the Slei^p of Plants that th^s im- p. 84. 



