1906] WIEGAND—BUDS AND TWIGS IN WINTER 383 
_ washed by WauirtTeN. Instead of whitewash, black paint was 
used to see if they might be made to open earlier. Two kinds of 
paint were prepared, one made of lamp black mixed with linseed 
oil, the other of lamp black and xylol. Buds and twigs of Syringa 
vulgaris, Ailanthus glandulosus, Populus dilatata, and apple were 
treated to a coat of oil paint; while some others of Syringa, Ailanthus, 
and apple were coated with xylol paint. The results were as follows: 
Syringa.—Xylol-painted buds much behind the normal during vernation; 
they looked unhealthy, one or two being entirely dead. Oil-painted buds never 
began to swell, all dead. 
Atlanthus.—The xylol paint made no difference with the killing back of 
the branches nor with the development of the buds. Oil paint prevented the 
swelling of the buds; they never opened. 
A pple.—Xylol-painted buds much behind the others; one completely dead. 
Oil-painted ones all dead. 
Populus dilatata.—Oil-painted buds showed much more rapid swelling than 
normal. When just opening the blackened buds were 6 to 8™™ longer. 
These results are evidently in the main exactly opposite what 
we were led to expect. I suspect that the explanation lies in this, 
that the coating of the surface of the bud with paint prevented res- 
piration, and thereby inhibited growth just as did varnish used 
on naked buds as described later in this paper, although it is possible 
that some toxic property of these substances might have had some- 
thing to do with the matter. The xylol furnished a much more 
porous layer than did the oil, and the inhibition was therefore much 
less. The buds of Populus dilatata are normally almost completely 
infiltrated with resin in the spaces between the organs and on the 
surface, and consequently may have some other means of obtaining 
oxygen for respiration. The coating even with oil paint, therefore, 
did not injure them. On the contrary, the black color seemed 
to cause an acceleration in growth. 
In concluding this part of the subject we may say that in the 
climate of New York, buds during the winter seem to remain in 
an almost dormant condition until a short time previous to their 
opening in the spring. In Missouri swelling of peach buds began 
much earlier than in New York. 
Color through its power of absorbing heat seems to have some 
effect upon the growth of buds in the spring. Early buds are in 
