STUDIES IN PLANT REGENERATION 205 
per surface of the piece. Accordingly, an attempt was made to 
secure a repetition of the result through experiment. 
Experiment 13.— The roots of several of these plants had 
forced their way through the openings at the bottom of the 
pots in which they were planted and had grown down into the 
gravel of the bench inthe greenhouse. These were removed from 
the plants and used as cuttings. Up to the present time, in all 
which have regenerated, the procedure has been the same as that 
mentioned above. Тһе shoots have all appeared from the middle 
of the pieces (Fig. 5). Specimens have recently been found in 
which some of these roots, 
while still on the plant, 
had sent up shoots. The 
gardener in charge says 
that this occasionally hap- 
pens in this and other 
plants when the roots are 
“ pot-bound." 
In all the root-parts ex- 
` perimented with, secondary 
roots grew ош rapidly, 
sometimes in a few days, 
or at most within а period 
of two weeks. These roots 
are not.to be regarded сн: Fic. 5. Root cutting of Pelargonium rad- 
true regenerations inas- ,/,т which has regenerated a shoot from the 
much as their production middle of the piece. 
tures with considerably more ease than to like structures. The 
results in root-cuttings and, as will be seen presently, in other 
plant parts as well, point to a different conclusion. The establish- 
ment of roots, both at places in which they normally occur, and as 
“ adventitious " organs is a far more general and rapid phenom- 
enon than the replacement of shoots. Less than half the kinds 
of roots used —and care was taken that all should be rich in a 
