188 
EYE SPY 
tendency to its offspring, and has therefore sur- 
vived in place of its ancient fellows, and is the 
type perpetuated or " selected " by nature. Such 
a tendril, then, is a modified leaf. How is it in 
the pea ? Here we find four leaflets in two oppo- 
site pairs, but no odd leaflet at the end of the main 
stalk, such as we see in almost all other plants of 
its family. But in place of 
} this leaflet we find a branch- 
^ 
If 
ing tendril reach- 
ing out on all sides for 
conquest. How quietly 
by the aid of these eager 
arms the sweet-pea climbs to the top of its brush ! 
In the common catbrier or smilax we see two 
slender thread-like tendrils growing from the base 
of each leaf. Here we have another modification, 
a development of the "stipule," that tiny pointed 
growth common to many leaves, and particularly 
notable at the base of a rose leaf. Still another 
plan has been evolved in the grape-vine. If we 
