356 BOTANICAL GAZETTE [NOVEMBER 
innovation is developed may bé taken as an index to the divergence 
from the original type. On this basis the most divergent species 
is E. americanum, with E. albidum and E. mesochoreum in order 
toward the type. Erythronium propullans is a special case, in 
which the bud axillary to the foliage leaf (text fig. 3, bud 2) in 
immature plants (as of EZ. americanum) is functional in the mature 
individuals, being elevated above the base of the bulb by the 
growth at the base of the aerial shoot, as this raises the base of the 
leaves to their final position. In floral characters it is most nearly 
related to E. albidum. The reduced size of the flower is probably 
Fic. 5.—Offshoot of E. propullans, showing structure and vascular elements in 
sections: A, C, on base of older offshoot B; }, bud of offshoot; c, cavity about bud. 
due in a measure to the interference with normal nutrition of the 
flower caused by the diversion of a portion of the vascular supply 
of the peduncle into the developing runner. The bud from which 
the lateral runner develops is inserted on the base of the peduncle 
in such a manner that in the early stages of growth as a runner 
the base of the peduncle elongates and thickens. As the clasp1ng 
petioles (sh, text fig. 5) hold the upper part of the peduncle from 
freely moving upward, the result of elongation is to form an elbow, 
with the bud at the convex side of the bend. At this stage all the 
vascular bundles are diverted with the general distortion of the 
base of the peduncle (A). As the runner pushes forward from the 
