102 ELEMENTS OF PLANT ANATOMY. 
primary stem, and since this is called a foot or podium we have 
the name monopodium. ‘These side axes may in their turn 
branch, producing stems of the third order, and these again till 
the system is completed. 
In the dichotomous system, the main axis discontinues its 
erowth, and two new branches start on the opposite sides of 
the stem apex at the same level. Each of these develops into 
a new axis which may branch again in a similar manner. 
There are several variations of these two methods ; for ex- 
ample, the sympodial method, which may be considered a special 
form of the monopodial. In this case, when the side branch 
starts to grow, the main axis ceases to develop. The side branch 
grows on and often takes an upward direction until it, in turn, 
branches ; it then ceases to grow, and its side branch grows on, 
prolonging the apparently simple axis, which is however, com- 
posed of lateral axes of different orders; hence the name sym- 
podium, an apparent axis, for this system. When the different 
branches composing this axis take an upward direction, the out- 
ward appearance of the stem so produced is so similar to the 
real monopodium that it is extremely difficult to distinguish its 
true character. ‘There are various other ways by which the 
normal order of both monopodial and dichotomous methods of 
branching is changed, but these three forms are most frequent. 
Among the ferns the branching is either dichotomous, mono- 
podial, or a combination of both. In the Salviniaceae and Mar- 
siliaceae it is plainly monopodial, while in many ferns it has not 
been determined whether the method of branching is monopodial 
or sympodial. In these doubtful cases the secondary branches 
cannot be said to be axillary, though their position may sustain 
a certain fixed relation to that of the leaf. They arise from the 
stem either at the side of the place of leaf insertion or above or 
below it, their bundle system being united to that of the stem 
in various ways. There are also other examples of dichotomous 
branching where the entire bundle system may be considered 
