1910] BLODGETT—BULBS OF ERYTHRONIUM 347 
apex alone develops into a bulb in most cases; but in older plants 
the axillary buds may also develop into bulbs. When the bulbs 
of any age are renewed im situ, the apical bud forms the single 
new bulb; but when there are runners developed, the axillary buds 
also form bulbs, being then the terminal buds of runners which 
become isolated in the soil as in the case of the primary bulb from 
the dropper. 
Second vegetative period 
The second vegetative period in the life cycle of the individual 
begins in September, when the roots protrude from the base of 
the primary bulb. These are few in number, three in most cases, 
and do not respond positively to gravitation. The root rudiments 
originate just below the region where the vascular strands from the 
dropper give off branches into the stem apex and the bulb scales. 
These stages are shown at r in figs. 24, 26, 27. The roots grow 
nearly straight from the point of origin to their limit of growth. 
They maintain a spatial relation toward each other so as to be 
equidistant in the soil. The oblique position of the base of the 
bulb makes the cluster of roots which radiate from the base appear 
lateral (Jost 14, p. 27) at the lower end of the bulb. In the 
older bulbs the roots are more numerous, and their lateral inser- 
tion is but slightly changed. The position of the roots in the soil . 
is such as to define a nearly flat cone, with its axis in line with 
the axis of the apical dome. The angle taken by the axis of the 
cone varies slightly as the obliquity of the individual bulb differs, 
but lies close to 45° to the vertical. Under experimental tests, 
different positions of the bulbs used did not change the position 
of the axis of the cone of roots in reference to the axis of the apical 
dome, although the latter was itself placed in abnormal positions 
i respect to the vertical. Roots are rarely found within the coni- 
al mass of soil outlined by most of the roots; when so found, 
_ the roots are very numerous and some are crowded away from the 
Peripheral portion of the meristem cells in the base of the bulb. 
During their growth from the point of their inception to the 
Surface of the bulb, the root rudiments pass through the tissues 
__ at the base of the bulb, a thickness of 1-3 mm. according to the size 
_ Of the bulb. In passing through the bulb the advancing tip of 
