Crown gall on Bryophyllum calycinum* 
MICHAEL LEVINE 
(WITH PLATE I0) 
In a paper on the effect of inoculations of Bacterium twme- 
faciens into the notches and midveins of detached leaves of 
Bryophyllum calycinum planted in moist sand, the present writer 
(Levine 1919) pointed out that in a great majority of cases the 
notches produced only crown galls of the common globular type 
without indications of leafy shoots. The inoculations into a 
midvein, however, invariably resulted in the development of 
only a crown gall. Inoculations of the crown gall organism 
alongside of the notches in these detached leaves yielded occa- 
sionally a crown gall with a dwarfed leafy shoot. Control leaves 
set out under similar conditions resulted in large and vigorously 
growing shoots in the time that it took the stunted leafy shoot 
and crown gall to develop. 
Inoculations of Bacterium tumefaciens into the region near 
the axillary buds of the stem caused the formation of a crown 
gall and a poorly developed axillary bud. Frequently the crown 
gall formed over its surface a number of leaflets. The axillary 
bud failed entirely in its development. 
Smith (1921) inoculated Bacterium tumefaciens into the 
notches of undetached leaves of Bryophyllum calycinum, which, 
he states, resulted in the development of shoots in the notches. 
He contends that Bacterium tumefaciens stimulated the devel- 
opment of these buds. Inoculations of the axillary bud of the 
stem with the same organism resulted in the two types of leafy 
crown galls described by me (Levine 1923). Smith’s results 
confirm my supposition that Bryophyllum has many totipotent 
cells. He fails, however, to show that these cells may be stimu- 
lated by Bacterium tumefaciens to form “‘embryomata” or 
leafy shoots in any region other than that where dormant buds 
are known to exist. 
In a later paper (Levine 1923) the writer reported studies on 
the effects of inoculations of Bacterium tumefaciens on the tobacco 
* Contribution from the Cancer Laboratory, Montefiore Hospital, New York. 
449 
