Igto] BLODGETT—BULBS OF ERYTHRONIUM 349 
one has been cut off; or if in handling the bulbs the roots present 
become dry, new roots are protruded among the bases of the old. 
In sections young rudiments are to be found in the basal tissue 
until nearly the close of the growing season. 
The roots have a well-developed endodermis, formed of two, 
or rarely three, cell layers just outside the usually triarch stele 
(figs. 21, 22). The endodermis is delicate in the seedling, but well 
developed in the older roots. 
The stem apex becomes more active after the roots are estab- 
lished in the soil, and develops the bulb rudiment from the apical 
bud. There are two axillary buds; one of these is in the axil of 
the first leaf (cotyledon), the base of which elongated to form the 
dropper, and on the death of the seedling dried out to form the 
husk. The other bud is axillary to the inner scale, which forms 
the bulk of the bulb as it lies in the soil until the second growing 
season begins. In the primary bulbs neither of these buds ordi- 
narily develops further ; but in older plants these, as well as the 
apical bud, form runners. During the mild periods of the winter 
and early spring the leaf is protruded from the bulb, and appears 
above the soil about the middle of March. The first leaves are 
about 1 cm. in width by 3-5 cm. in length, a little more tapering 
than the older leaves, but in other respects like them. They last 
for six to eight weeks, and then disappear by retrogressive withering. 
During their activity the bulb rudiment at the base of the petiole 
enlarges to its full size as the secondary bulb. 
The starch stored in the primary bulb is used in part in the 
formation of the aerial structure (foliage leaf), in part also in the 
building of the new bulb. The bulb gradually disappears as the 
new bulb develops, the older tissues becoming free from starch and 
reacting to the F ehling test for sugar as the season advances and 
the new bulb enlarges. When the leaf begins to wither, in late 
May, there is practically nothing left of the primary bulb except 
its husk; this still incloses the base of the petiole, which forms the 
husk of the secondary bulb. After the death of the foliage leaf, 
the bulb is dormant until the roots are developed in September, 
as the first step in the third vegetative season. But in the interval 
the stem apex organizes the foliage leaf, and organizes the buds 
