
PLANT GEOGRAPHY 44) 
Climbing vines are scarce and confined chiefly to the edges of 
the forests. Epiphytes are also scanty and, except in the warmer 
parts of temperate zones, consist only of bryophytes, lichens, and 
alow. ‘The best development of deciduous forests occurs in 
the eastern portion of the 
United States. 
During the winter sea- 
son the buds of most of 
the species are protected 
by specialized scales which 
prevent the buds from be- 
ing desiccated (Fig. 94). 
The time of growth and 
development of the leaves 
is determined by the sea- 
sons. The winter buds con- 
tain the flowers and leaves 
of the coming spring and 
summer. The flowers usu- 
ally expand at the begin- 
ning of the growing season, 
before the leaves appear 
or are fully developed. 
The leaf buds open and 
the leaves expand very 
rapidly. The foliage is 
fully developed early in 
the season, and the ex- 
pansion of new leaves then 
ceases. During the latter 
part of the season the buds that will expand during the next 
spring are formed, and food material, which will make possible 
rapid growth in the spring, is stored in the stems. 
The expansion of the foliage early in the season is of great 
advantage, as it allows all the leaves to function for the great- 
est possible length of time. The early appearance of flowers 

Fic. 495. Redwood forest, Humboldt 
County, California 
