178 
MORPHOLOGY OF MEMBERS. 
Just as the dichotomy may consist of numerous bifurcations, so may a mono- 
podium consist of several orders of monopodial branching. 
These definitions refer only to the bud-condition of the branch-system. Not 
unfrequently, both in dichotomous and in monopodial systems, the original character 
is maintained in their further growth; the two bifurcations develope, in the case 
of dichotomy, with equal strength and branch uniformly ; in the case of a mono- 
podium the primary axis continues to grow more strongly than all the secondary 
axes, and branches more copiously. But it is very commonly the case that in 
a dichotomous system some of the bifurcations are weaker, or that in a mono- 
podial system some of the lateral axes, soon after their formation, grow more 
strongly and branch more copiously than 
the primary axis. In such cases the ori- 
ginal character of the branch- system be- 
comes less and less evident as it developes ; 
and it may happen that systems originally 
dichotomous have subsequently the appear- 
ance of monopodia, and vice versa. It is 
hence impossible to infer from a mature 
system whether it originated in dichotomy 
or in lateral branching. It will therefore 
be desirable to make a simple classification 
of the most important changes which a 
branch-system undergoes during the de- 
velopment of its members. 
(i) The Development of Dichotomous 
Systems may take place either in a bifurcate 
or a sympodial manner ; I call a system 
bifurcate when at each fork the two 
branches develope with equal strength, as 
in Fig. 134, A. The dichotomous system is 
developed sympodially when at each bifurcation one branch developes more strongly 
than the other ; in this case the base of each successive bifurcation forms apparently 
a primary shoot, on which the weaker branches appear as lateral shoots (Fig. 134, 
C). The apparent primary shoot, which in fact consists of the bases of consecutive 
bifurcations, may on this account be termed a Pseud-axis or Sympodiw?t. Thus in B 
(Fig. 134) the sympodium is composed of the left-hand branches I, I, I; in C of the 
alternate left and right-hand branches / r, I r. Whether the case represented in B, 
which, on account of its similarity to certain monopodial systems, may be termed a 
Helicoid (bostrychold) Dichotomy, actu'ally occurs is doubtful (it probably does how- 
ever in the leaf of Adiantum pedatum). On the other hand the development repre- 
sented in Fig. 134, C is common in shoots of Selaginellese, and, on account of its 
resemblance to some monopodial systems, may be termed a Scorpioid (cicinal) 
Dichotomy ^. 
(2) The development of Monopodial Systems may take place in a racemose 
Fig. 134.— Diagram of the various modes of develop- 
ment of a dichotomy ; A one developed in a bifurcate 
manner ; B a helicoid ; C a scorpioid dichotomy. 
^ On Dichotomous Inflorescences see Book II, Phanerogams, 
