406 Boewig on the Histology and 
over the surface of the fruit, and a blackening of the cotyle- 
dons with considerable or entire loss of roots and root hairs. 
These agree with the natural conditions of the plant. The 
best soil was almost pure sand. Under such conditions seeds 
germinated in three to four weeks. 
3. Seedling Growth.—The radicle and hypocotyl find their 
way out of the seed by the micropyle, forcing the shell apart 
slightly by a single median split, which is, however, not at 
all extensive and exercises some elasticity, for while the 
hypocotyl when it first emerges is rather fleshy, it is not 
nearly so large as it becomes later on when entirely outside 
the seed. The lowermost part of the hypocotyl is a fleshy, 
cylindrical body, fifteen mm. long or less, of a pale yellow 
color, and is glabrous like the rest of the plant. As it 
emerges from the seed the food substance is rapidly passed 
from the cotyledons into it, causing it to become very turgid. 
The food is not reconverted into starch in the hypocotyl, but 
remains dissolved in the cell sap as sugar. At the lower 
end is a tiny root that is reduced to a mere conical tooth. 
In a circular zone above and around this, four side roots 
typically develop (Plate xxxiii, Fig. 4), which soon out- 
strip the main root and may reach considerable length. In 
some seedlings three, two (or even one) side roots develop, 
which are then somewhat stouter than when there are four. 
Above, the hypocotyl] attenuates rapidly into a thin, almost 
filamentous, but bright green stem, which is at first bent 
downward with its plumule in the seed (Fig. 4, a) ; it usually 
rights itself by the time its length equals that of the fleshy 
portion, and in most cases carries up with it the now empty 
seed (Fig. 4, b), which, because of its firm, elastic shell, is 
difficult to strip off. One seedling, fully six inches high, still 
bore the empty seed at its tip with the shell unbroken, and 
owing to the rather unfortunate growth of two leaves on the 
portion within the seed, these had become caught and the 
stem confined within had curled round one and one-half 
times inside the empty seed. Another seedling, on the other 
