34 THE STEM. 



How 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 tlie storms of life iirndy 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 

 futiu'e? 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 Epiphytes (from ejyi^ w^ow^ phiiton^ a plant) grow 

 without roots ; they are called Ae7'ial^ or air plcmts ; 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 vegetahle camel. The E]ndendTurt% 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 being 

 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 YII. 



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 upon a 

 branch of the whortleberry ; its color was a bright crimson, which contrasted beautifully with the 

 white flowers and green leaves of the plant on which it grew. 



Parasitic plants — Air plants. — a. Proper time to collect roots for medicin;il purposes. — 40. The Stem. 



