184 BOTANICAL GAZETTE [FEBRUARY 
growing points (fig. 8). These were evident when the plants were. 
very small. As the plants became older, one of the growing points 
was not infrequently outgrown by the stronger branch. In other 
instances the two growing points maintained almost equal vigor, 
producing two well developed stalks which finally blossomed. In 
the Maryland Mammoth variety there seems to be a tendency to 
develop bifurcation of the main stem in a small percentage of the 
plants. This feature, however, has 
usually made its appearance rather 
late in the development of the plant. 
Corolla lobes abnormal in number 
In the normal tobacco blossom the 
corolla has 5 lobes and 5 stamens. In 
abnormal blossoms the number of 
Fic. 10.—N. Tabacum, show- 
ing abnormal form at left, with 
only 2 petals; normal blossom 
with 5 petals from same plant 
shown at right; this singular 
blossom occurred on a plant of 
second generation of a cross be- 
corolla lobes may be greater or less 
than the normal number. Blossoms 
abnormal with respect to the number 
of corolla lobes are shown in figs. 9 
and 1o. The blossoms in the top row 
(fig. 9) were obtained from a plant of 
tween 2 distinct varieties of 
N. Tabacum, and was the only 
abnormal blossom produced by 
plant.—T. I. 21 
the second generation of the cross 
N. Tabacum (2) XN. silvestris (2), and 
were a deep red. Nearly all the blos- 
soms produced by the plant possessed 
6 or 7 corolla lobes. A few normal blossoms were produced. The 
plant was grown in an 8-inch pot and appeared to be normal in 
all respects. 
The blossoms shown in fig. 9, rows 2 and 3, were obtained from 
a single plant of ordinary tobacco (N. Tabacum) and were pink 
in color. Although a few blossoms possessed the normal number 
of corolla lobes (5), the majority possessed only 3 or 4 lobes. The 
plant producing these blossoms showed typical symptoms of 
“‘Frenching,”’ which appears to be a nutritional disturbance asso- 
ciated with unfavorable soil conditions. This plant was grown in 
an 8-inch pot. 
