BUDS AND BRANCHES 133 
move the scales one by one, representing the number and 
position of the pairs by a diagram after the model given in 
Fig. 150. In the bud of an alternately branched twig the 
order will be different, and the diagram must be varied ac- 
cordingly. Do you observe any difference 
as to size and texture between the outer 
and inner scales? Notice how the former 
inclose the tenderer parts within like a 
protecting wall. In cold climates the outer 
scales are frequently 
coated with gum, as in gag. 150. — Dia 
the horse-chestnut, for gram of opposite bud 
: ; scales. 
greater security against 
the weather. The hickory and various 
other trees have the inner scales covered 
with fur or down that envelops the tender 
bud like a warm blanket. 
149. Nature of the scales. — The posi- 
tion of the scales shows that they occupy 
the place of leaves or of some part of a 
leaf. In expanding buds of the lilac and 
many other plants, they can be found in 
all stages of transition, from scales to 
true leaves. In the buckeye and horse- 
chestnut, they will easily be recognized 
"as modified leaf stalks (Fig. 151). In the 
tulip tree, magnolia, India rubber tree, 
fig, elm, and many others, they represent 
Fig. 151.— Devel- ‘ 
opment of the partsof appendages called stipules, often found at 
Ee san the bases of leaves. (See 165, 166.) In 
er GRAY.) : : : 
this case a pair of scales is attached with 
each separate leaflet, and as the growing axis lengthens in 
spring, they are carried apart by the elongation of the inter- 
nodes so that the scars are separated, a pair at each node, 
making rings all along the stem, as shown in Fig. 152, in- 
stead of having them compacted into bands at the base of 
