40 OP THE STEM. 



price! Who would not rather, like the mountain oak, meet the 

 storms of life firmly rooted in virtuous principles, than to 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 fiinid some roots growing on other plants, and appearing to de- 

 rive sustenance from their juices. These are called parasites ; this 

 term is often applied to persons who are willing to live in depend- 

 ance upon others; and so despicable does this trait of character ap- 

 pear, that we almost conceive it a kind of meanness, even for a: plant 

 to hve without elaborating its own food. Parasitic plants are com- 

 mon in tropical regions ; sometimes many kinds are found upon the 

 same tree, presenting a curious variety 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' eel 

 ebrated parasitic plants. 



Some plants grow without roots ; these are called air plants .• they 

 are furnished v;ith leaves or stems which seem to inhale, but not to 

 exhale ^mds ; their substance is usually fleshy and juicy; some of 

 fhem flourish in the most dry and sandy places, exposed to a burning 

 sun ; as the Stapelta, sometimes called the vegetable camel. The 

 Epidendrum grows and blossoms for years, suspended from the 

 ceiling of a room, and nourished only by air. 



Many roots, as the rhubarb, wild-turnip, blood-root, &c. possess 

 important medicinal properties. 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, because their peculiar virtues are then most 

 concentrated 



LECTURE VII. 



OF THE STEM. 



The stem is the body of a plant, whether it be a tree like the oak, 

 a shrub like the lilac, or an herb like the poppy ; its use is to sustain 

 the branches, leaves, and flowers, and to serve as an organ of com- 

 inunication between them and the root, conducting from the latter to 

 the former, the animal and vegetable substances, salts, and earthy 

 matter, which the radicles, by their mouths, suck up for the nourish- 

 ment of the plant. The influence of light and air is, through the 

 medium of the stem, conveyed from the leaves to the root. 



* In the vicinity of Troy, I have seen a very beautiful species of the Ptcrospora, 

 growing upon a branch of the whortleberry. Its colour was a bright crimson, which 

 contrasted finely with the white flowers and green leaves of the plant on which it 

 grew. 



Parasitic plants— Air plants— Proper time to collect roots for medicinal purposes — 

 Stem, its use. 



