100 

Frq. 95. A branch of 
the Hrythrina indica, 
a tropical tree which 
is leafless during the 
dry season 
This branch is marked 
by three rings of scars 
left by the falling of 
scales which protected 
the bud during succes- 
sive dry seasons. The 
three rings show that 
the lower part of the 
branch is four years 
old. (x 4) 
in the formation of rings of bud-scale 
A TEXTBOOK OF GENERAL BOTANY 
described in the preceding chapter. When 
bud scales fall, they leave scars, just as do 
ordinary leaves. Usually, however, the 
scars of bud scales are considerably smaller _ 
and much more crowded together than are 
those of ordinary leaves. The result is that 
when the scales around a dormant bud fall, 
the crowded bud-scale scars frequently form 
a conspicuous ring around the stem and 
thus enable us to determine much of the 
history of that stem. A season’s growth 
always begins just above a ring of bud- 
scale scars and ends with the formation of. 
a new set of scales, 
so that by counting 
the rings of bud- 
scale scars we can 
tell the age of a 
branch. Also, by 
examination of the 
part of the stem be- 
tween the rings we 
ean tell how much 
growth was made 
during past seasons 
and the number of 
leaves borne by the 
branch during those 
seasons. The fall- 
ing of leaves which 
results in leafless 
branches and_ also 

Fia. 96. Opposite leaves 
on an upright branch of 
guava (Psidium guajava) 
Compare position of leaves 
in Fig. 91. (x 4) 
scars may be connected with either a 
long cold season or a severe dry season (Fig. 95). Trees which 
do not shed their leaves may have their branches marked by 
