334 BOTANICAL GAZETTE [NOVEMBER 
a ringlike peg is laid down in the formation of the seed, and with 
germination this enlarges somewhat. In these forms, therefore, 
the peg is a natural outgrowth approximately equal on all flanks 
of the seeds; its appearance and development are related, undoubt- 
edly, to the plant form and not called forth alone by external 
stimuli. We find that such a ringlike peg, rather small but approx- 
imately equal on all flanks, develops on the seedling of palo verde 
(green-stemmed Parkinsonia). In this form the arching of the 
hypocotyl is not marked and the peg does not function in the 
removal of the coat; likewise, external conditions do not seem 
to lead to a lateral placement. Results already stated, as well as 
data to be stated later, lead us to believe 
that the peg of the cucurbits is, to a con- 
siderable degree, a natural outgrowth of the 
seedling, and that it is approximately equal 
on all flanks if arching is avoided. Wemust 
of course accept the quantitative greater 
development on the two broader faces of 
the hypocotyl over the two narrower. It 
is also evident that in different species the 
size of the outgrowth varies greatly; 1 15 
relatively large in squashes (Hubbard, Bos- 
ton marrow, and Calhoun), and relatively 
small or even absent in pumpkins (Big Tom 
and Sugar pie). We have also found the 
latter to be the case in various watermel- 
ons and cucumbers. In fact, if arching 3S 
avoided, different species will show all the 
intermediate forms from the so-called pegless (fig. 6) to those that 
have very prominent ringlike pegs. We must also recognize that 
the contact of coats, as figs. 2 and 3 show, greatly increases the size 
of this outgrowth. The size is also greatly increased, at least oP 
one flank, by arching. oe 
The question, therefore, does not seem to be so much wha 
stimuli cause the development of this organ, as DARWIN and nee 
assumed, but rather what stimuli lead to its lateral placemen 
and tend to increase its size. 
Fic. 6.—Pegless seed- 
lings of Big Tom. 
