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Igt0] BLODGETT—BULBS OF ERYTHRONIUM 359 
through the tip of the runner, just as the runners burst the petiole 
sheath when first issuing from the bulb. The next scale of the 
bulb rudiment forms the runner extension, and the stem apex 
with a small scale is carried forward as if under normal conditions. 
The necessary nourishment for the added growth comes from the 
parent plant, through the stalk of the runner to the point where 
the terminal bud was inserted. Then the vascular bundles of the 
bud, following down through the bud scale, convey material to 
the stem apex in the tip of the extension of the runner. In two 
cases, in the spring of 1908, this extension of the runner by the 
protrusion of the terminal bud through the end of the runner 
sheath had been repeated a second time. 
Development of the mature plants 
The production of the flowers, which mark the maturity of the 
individual plant and the termination of the cycle of stages from 
seed to seed (text fig. 6), is associated with several changes from 
the manner of development followed during the immature con- 
dition. During the whole period from seedling to this stage, the 
primary stem apex has persisted, and from it have come the suc- 
cessive leaf rudiments which developed into either bulb scales or 
foliage leaves as the conditions demanded. The accompanying 
tabular view of the activity of the primary stem apex will show 
the general relation of these leaf rudiments. In addition to the 
outgrowths from the apical dome in the form of leaf rudiments, 
there have been various buds, axillary to the inner scale, which 
were laid down by the stem apex from time to time. The leaf 
Tudiments developed in these axillary buds are not considered 
in the tabulated series of products from the stem apex. The bud 
in the axil of the outer scale does not arise from the apical tissue 
directly, but from the mass of meristem at the base of the scales. 
The final structure developed from the primary stem apex, 
after passing through the immature stages, is the flower bud of 
the mature individual. In the immature stages the apical dome 
persists at the base of the bulb, producing successively the several 
bulb scales and foliage leaves. In the mature bulb the apical 
dome becomes surrounded by the foliage leaf rudiments (fig. 25), 
