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lengthening, vertically, of the first layer of cells under the epi- 
dermis of the upper surface, but no further differentiation, merely 
a growth in size and number of cells. 
The bud grown in light had developed in six days (April 23) 
as follows: (c) The entire bud had lengthened, being now I 4 cm.; 
all but one scale had fallen off. The outer, lower leaf was 34 cm. 
long and ofa delicate green color, the leaves showed no sign of 
hyponasty, but were closely folded around the stem. The bud 
was then cross sectioned to see the anatomical changes, if such 
had occurred. The outer lower leaf showed a slight indication of 
palisade tissue by the lengthening of the first row of cells under 
the upper epidermis (d.) This surface had not been exposed to 
direct rays of light, the under surface directly exposed to light 
showed no sign of palisade tissue. These facts indicate that the 
formation of palisade tissue is the result of an inherent quality of 
the leaf, only assisted and not induced by light. 
An inner, upper leaf of the bud, still enclosed by the outer 
leaves on the cross section, showed no differentiation of palisade 
and spongy tissue. 
On April 27th, on examining the bud grown in light, we find 
a different morphology and far greater anatomical changes than in 
the etiolated bud grown the same length of time. The bud is 1% 
cm. long, the outer lower leaf 1 cm. long, large leaf and short 
internodes as opposed to small leaves and long internodes of the 
etiolated bud examined. This outer leaf forms a small angle with 
its stem for 34 of its length when its upper surface has grown very 
rapidly, so that the remaining ¥4 of the blade makes an angle of 
go° with the stem, so that this part of the surface receives direct 
rays from the sun. This leaf is bright green. On examination 
by cross sectioning we see decided development; a well formed 
layer of palisade tissue under upper epidermis, spongy tissues 
on under surface, many stomata and large air spaces. 
On April 30th, after two weeks’ growth, the leaves are open- 
ing still further. The outer lower leaf, corresponding to the leaf 
studied, April 27th, makes an angle of 45°, half its length from 
the base and the rest of the way an angle of 90°. The second 
leaf just above is at an angle of 45° throughout its entire length. 
The other leaves are still folded about the stem. The anatomical 
