328 BOTANICAL GAZETTE [NOVEMBER 
tact of coats as a stimulus to arching. By a comparison of figs. 2 
and 3, one can see clearly the effect of contact upon the size of the 
peg. 
A culture of pumpkin (Big Tom), with coats removed, radicles 
pointing vertically downward, and grown in a spray as described 
above, produced 39 seedlings. Of these none were sharply arched; 
19 showed very small two-sided pegs; 19 were essentially pegless; 
and 1 showed a small one-sided peg on the concave side of the 
slight arch. A similar culture of the pumpkin (Big Tom) with 
coats intact gave 31 seedlings; of these, 25 were sharply arched, 
with pegs entirely on the concave side of the arch; 1 was little 
arched, with peg on concave side of arch; 3 were pegless; and 2 
had equal, small, two-sided pegs. From these data it is evident 
that in the pumpkin (Big Tom) contact of coats is even more 
effective in producing arching than in the squash (Hubbard), 
and unlike the case of the squash, the arching shifts the peg entirely 
to the concave side of the arch. From the large number of peg- 
less seedlings appearing in the culture with the coats removed, it 
is also evident that the arch not only determines the lateral place- 
ment of the peg, but in some cases even its appearance. One may 
be inclined to think the existence of the peg is perhaps determined 
by the contact of the coat, rather than by the arching produced 
by the coat; but it is not probable, for of the 6 not arched in the 
culture with coats on, 3 are pegless. It is apparent, therefore, 
that a large number of the pumpkins (Big Tom) are pegless if 
developed without considerable arching, and that arching deter- 
mines in about half the cases whether or not there will be 4 pe 
as well as the placement of the peg on the concave side of the arch. 
Fig. 4 shows a culture of pumpkin (Big Tom) with coats removed 
at the tips, and grown on the horizontal clinostat in a spray- 
the 30 seedlings in the culture, none are sharply arched; 14 have 
small two-sided pegs; 8 show slight pegs on the concave side of 
the slight arch; and 8 are essentially pegless. Fig. 5 shows @ 
similar culture except the coats are intact. Of the 24 seedlings, 
20 are sharply arched, with pegs entirely on the concave side of 
the arch; 2 are slightly arched, one of which has an equal two- 
sided peg and the other a slight one on the concave side of the arch; 
