THE STEM. 55 
than the former. Adanson mentions having seen in the 
Cape Verd Islands some Baobabs about 30 feet in diameter, 
or nearly 100 feet in circumference. These are the largest 
trees in the world. Heat and moisture enable trees to grow 
to a considerable magnitude: and hence the largest trees 
are found in tropical climes. 
CHAP. IlI.—_BUDS. 
179. Buws are those little bodies which grow on the sur- 
faces of vegetables, and contain, in a dormant, or rather la- 
tent state, the germ or rudiment of an entire plant, or of part 
of a plant, ready to be developed when the season is favour- 
able, and capable of growing or being enlarged in two oppo- 
site directions. Buds are closely connected with or originate 
from the pith or medullary matter of the stem. They are 
the first results of vegetation, and the leaves, branches, and 
flowers are at first contained in buds. The period of their 
Those in a hot-house, or in a warm exposure, are first de- 
veloped. Severe cold destroys them altogether. 
180. It is the opinion of many botanists, that germs or ru- 
diments of huds exist within the plant, and are formed at the 
same time as the stem and branches ; that those only become 
developed which meet with an abundant supply of sap, aris- 
ing from some obstruction in its course, which causes it to 
accumulate : that they develope as leaves and branches, or as 
roots, according to the medium in which they shoot, becom- 
and roots when they strike into the earth ; and that the buds 
arise at the axilla of the leaf (between the leaf and the stem, 
at the angle formed by their meeting), because the branching . 
‘sila of aul anda brat, motto of he and 
ing buds (generally so called) when exposed to light and air, 
off of the fibres of the leaf from the stem impedes the sap in 
itso course at these particular parts. A bud may be o observed es 
