294 M. WICHURA ON THE WINDING OF LEAVES. 



the inflorescence appears reversed, so that the labellum comes 

 to the front, while in its original position it is turned towards 

 the axis. No definite direction can be detected in this winding ; 

 right- and left-wound ovaries succeed one another quite irregu- 

 larly. It is possible that this revolution is a mere effect of 

 irritability, caused by the effort of the labellum to assume an 

 external position, corresponding to its greater proportionate de- 

 velopment. 



74. 

 Aroidece. Acorus Calamus, L. : stem-leaves left. 



75. 



Typhacea. Typha lattfolia, L. ; T. angustifolia, L. ; T. ste- 

 nophylla $ Sparganium ramosum, Huds. : stem-leaves left. Spar- 

 ganium natans, L. : stem-leaves right. The only example I 

 know of a plant winding under water. The winding may be 

 frequently prevented, or its effects renderea imperceptible even by 

 slow flowing of the water. But I observed it very clearly in 

 July 1847, on the heath behind Moabit, near Berlin, in little 

 pools where the undisturbed development of the leaves was 

 favoured by the calm and clearness of the water. 



76. 



Pdlma. Maximiliana insignis, Mart. : anthers mostly right-, 

 but occasionally left-wound. 



77. 



Coniferce. For the acicular leaves of the species of Pinus, 

 see 45. Podocarpus elongatus, L'Herit. ; P. macrophyllus, 

 Wall. ; P.falcatus, L'Herit., and P. latifolius, Wall. : stalks of 

 the stem-leaves and lowest part of the blades right. 



78- 



Casuarinece. Casuarina suberosa, Otto and Dietr., and a 

 Casuarina from Cuming, discovered in the Philippines and 

 distributed as No. 730 : sheath-teeth right. Casuarina humilis, 

 Otto and Dietr. ; C. quadrivalvis, Labill., and C. suberosa, Otto 

 and Dietr. : style left. 



