711 
angular leaf, such as, according VELENOVSKY, characterizes dichotomy 
in ferns *). 
In this process however, one of the two branches may also be 
smaller than the other, in which case the larger branch places itself 
entirely in the prolongation of the base. These cases gradually pass 
into such in which one branch forms in every respect a prolongation 
of the base, and the other is placed next to an ordinary leaf of the 
stem as a thin branch or small lateral bud; this leaf we may then 
still regard as the angular leaf of the dichotomy. 
From these observations we may deduce that probably all bran- 
chings in ferns, including those by means of VELENOvsKY’s “stable 
adventitious buds’, are to be referred to one and the same process 
and also that it is not permissible to consider the lateral buds of 
ferns as adventitious buds. It then further becomes highly probable 
that the axillary branching of Gymnosperms and Angiosperms is due 
to the same process. The only points of difference between the lateral 
branching of ferns and that of these groups, are that in ferns the 
bud is not always placed above the insertion of the leaf and that 
by no means all leaves produce buds. 
In the Conifers we find already an intermediate stage to the extent 
that by no means all leaves have axillary buds, whilst in the eycads 
another intermediate stage seems to the found, for in this group the 
rare non-adventitious buds appear to be placed, not above, but next 
to the corresponding leaf *). 
If this is so then, the normal dichotomy, which occurs in rare cases 
among Angiosperms*) is a different, nev process, a dichotomy of 
the second order, as it were. 
1) 1. c. p. 246. 
2) E. WarminG, Undersdgelser og Betragtninger over Cycadeerne. Oversigt K. 
Danske Vidensk. Selsk. Forh. 1877 p. 91. — H. Graf von Soms LauBacH, Die 
Spoorsfolge der Stangeria und der übrigen Cycadeen. Bot Zeitung 48, 1890, p. 197. 
5) See my article “Ueber die Verästelung bei monokotylen Bäumen II. Die 
Verästelung von Hyphaene”, in Recueil des Tray. botan. Néerl. Vol. 6 1909 p. 211. 
The opinion expressed there on p. 232 that the dichotomy of Hyphaene is the 
first case described in the literature of dichotomy in a phanerogam is incorrect 
since CHURCH in his ‘Relation of phyllotaxis to mechanical laws’ (London i904) 
in the “notes and errata” at the end of the book (p. 352) already described the 
dichotomy of fasciated heads of Helianthus. 
