THE STKM. 91 



nine feet in circumference, and weighing fifteen pounds ! Its color 

 is light orange, mottled with yellowish-white. 



153. Among Cryptogamous plants, numerous Fungi are parasitic 

 upon living, especially upon languishing vegetables ; others infest 

 living animals ; the rest feed on dead or decaying vegetable or 

 animal matters : all are destitute of chlorophyll or anything like 

 green herbage. It is jirobable that our Monotropa, .or Indian Pipe, 

 a pallid Phasnogamous plant, looking like a Fungus, actually Uves 

 like one, and draws its nourishment, at least in great part, from the 

 decaying leaves among which it grows. 



CHAPTER lY 



♦ift-: 



OP THE STEM, OR ASCENDING AXIS. 

 Sect. I. Its General Characteristics and Mode of Growth. 



154. The Stem is the ascending axis, or that portion of the trunk 

 Avhich in tlie embryo grows in an ojiposite direction from the root, 

 seeking the light, and exposing itself as much as possible to the air. 

 All Pha^nogamous plants (114) possess stems. Li those which are 

 said to be acaulescent, or stemless, it is either very shoi't, or concealed 

 beneath the gi'ound. Although the stem always takes an ascending 

 direction at the commencement of its growth, it does not uniformlv 

 retain it ; but sometimes trails along the surface of the ground, or 

 burrows beneath it, sending up branches, flower-stalks, or leaves 

 into the air. The common idea, that all the subterranean portion 

 of a plant belongs to the root, is by no means correct. 



155. The root gives birth to no other organs, but itself directly 

 performs those functions which pertain to the relations of the vege- 

 table with the soil ; — its branches bind the plant to the earth ; its 

 newly formed extremities or rootlets imbibe nourishment from it.. 

 But the aerial functions of vegetation are chiefly carried on, not so 

 much by the stem itself as by a distinct set of organs which it bears, 

 namely, the leaves. Hence, the production of leaves is one of the 



