54 
THE STEM. 
IIow strikingly analogous this poor weed to many a human 
being, blown about on the ocean of life, by every breath of 
passion or caprice ! Who would not rather, like the mount- 
ain oak, meet the storms of life firmly rooted in virtuous prin- 
ciples, than be floated along, even by the breath of pleasure, 
without end or aim, forgetful of the past, and careless of the 
future? To the virtuous, afflictions serve but to strengthen 
them in goodness ; so, 
" Yonder oaks ! superior to the power 
Of all the warring winds of heaven do rise, 
And from the stormy promontory tower ; 
While each assailing blast increase of strength supplies." 
We find some roots growing on plants, and deriving sus- 
tenance from their juices. These are called jparasites. Para- 
sitic plants are common in tropical regions ; sometimes many 
kinds are found upon the same tree, presenting a curious vari- 
ety of foliage. In our climate, except in the Cryptogamous 
family, as lichens, mosses, &c., we have but few genera of these 
plants.* The dodder and mistletoe are celebrated parasitic 
plants. The E])ij[)hytes (from epi^ upon, jphuton^ a plant) grow 
without roots ; they are called Aerial^ or air plants / their 
substance is usually fleshy and juicy ; some of them flourish in 
the most dry and sandy places exposed to a burning sun ; as 
the Stapelia^ or mgetctble camel. The Epidendrum grows and 
blossoms for years, suspended from the ceiling of a room, and 
nourished only by air. The Tillandsia, or black moss, so com- 
mon in southern regions, belongs to this class of plants ; its 
long, gray festoons draping the forests, as they extend from 
tree to tree, give them a peculiar appearance. 
The growth of the root is most rapid in autumn ; at this season, the sun bemg 
less powerful, and the air more charged with moisture, the juices condense in the 
lower part of the plant, and nourish it ; but as the season becomes cold, vegetation 
is checked. The winter is the best time to collect roots for medicinal purposes, be- 
cause their peculiar virtues are then most concentrated. 
LECTUEE YIl. 
STEM. 
40. The Stem is the body of a plant ; its use is to sustain the 
branches, leaves, and flowers, and to serve as an organ of com- 
• In the vicinity of Troy I have seen a very beautiful species of the Pterospora, growing npon a 
branch of the whortleberry ; its color was a bright crimson, whicfci contrasted beautifully with the 
while flowers and green leaves of the plant on which it grew. 
Parasitij plants — Air plants. — a. Proper time to collect roots for medicinal purposes. — 40. The Stem 
