METHODS 



cut off from two of its surfaces. 



whose apices are just turning upward, showed in one case five apical 



it was impossible to say which was the original one. Some 



>f the iin had not others one or mote seg- 



l had been cut off. The original apex continues its growth upward. 



e secondary initial cells are left behind, but later they may give 



rise to ventral shoots. 



.-I. Male plant of Pallavitimia (A/illrmfl) Zotteifrn 

 B. Sterile plant of P. ndifulota. natural tiie ; r. ventral 



One of these secondary apical cells begins active growth and gives 



'\ continues the sympodium. It grows horizontally 



for a litre, hut finally turns upward and develops into the next upright 



green froml. Several segments are cut off from the apical cell before 



a differentiation of the different tissues of the shoot is apparent. Finally 



the midrib and lateral wings can be distinguished, and in the former the 



il strand of elongated cells appears. Thus, at the base of the shoot, 



