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116 MISSOURI BOTANICAL GARDEN. 
recovery that does not occur in the former case, nor in the 
one following. We are here concerned only with the origin 
of new growths, since all exposed growths have been com- 
pletely killed. 
Liriodendron tulipifera. All unfolded leaves were, of 
course, completely killed. Each leaf is, however, unfolded 
independently from the former one, and separated from it 
by the protective opening scales. Those so protected by 
the scales proceeded to grow, and, although a long time 
developing completely, were among the first to start, since 
their growing period was not shortened. The dropping off 
of foliage later in the season cannot be taken as any frost 
indication, since this condition occurs nearly every season, 
probably as a result of smoke injury. 
Ginkgo biloba. This is a broad-leaved Gymnosperm 
which bears its leaves in clusters, of which the outer leaves 
are the older, and the inner the younger. The new leaves 
come forth from the center of the cluster one at a time. 
The freeze killed all of the opened leaves, which then turned 
brown and hung on until the middle of summer. The 
new leaves started to come out again within a few days 
after the frost, but their appearance was largely hidden until 
after the falling of the killed leaves. At the end of the 
season their appearance was much better than those of 
Liriodendron. 
In both of the above cases the recovery has been rapid 
solely because the growth of new leaves did not involve the 
production of new buds, but simply a continuation of 
development in the buds that had already started, or more 
correctly, in the development of the uninjured shoot. 
Upon the death of many of the leaves on shoots which 
were not injured, there was an immediate development of 
the unopened buds, as was the case with Cercis canadensis 
and Cladrastis tinctoria. In the latter the leaflets shrivelled 
up and fell off, the petiole remaining for some weeks, when 
it, too, fell, or was pushed off by the bud enclosed in its 
base. In this case we have a development of four separate 
