KINDS OF STEM AND BKANCHES. 103 



157. Propagation from Buds, Buds, being, as it were, new indi- 

 viduals springing from the original stem, may be removed and 

 attached to other parts of the parent trunk, or to that of another 

 individual of the same, or even of a different, but nearly related 

 species, where they will grow equally well. This is directly ac- 

 complished in the operation of budding. In ingrafting, the bud is 

 transferred, along with a portion of the shoot on which it grew. 

 Moreover, as the cut end of such shoots, when buried in moist and 

 warm soil, will commonly, under due care, send out adventitious 

 roots, they may be made to grow independently, drawing their 

 nourishment immediately from the soil, instead of indirectly 

 through the parent trunk. This is done in the propagation of 

 plants by cuttings. The great importance of these horticultural 

 operations rests chiefly on the well-known fact, that buds propa- 

 gate individual peculiarities, or varieties, which are commonly 

 lost in raising plants from the seed. 



SECT. III. THE KINDS OF STEM AND BRANCHES. 



158. On the size and duration of the stem the oldest and most 

 obvious division of plants is founded, namely, into Herbs, Shrubs, 

 and Trees. 



159. Herbs are plants in which the stem does not become woody 

 and persistent, but dies annually or after flowering, down to the 

 ground at least. The difference between annual, biennial, and 

 perennial herbs has already been pointed out (127-130). The 

 same species is so often either annual or biennial, according to cir- 

 cumstances or the mode of management, that it is convenient to 

 have a common name for plants that flower and fruit but once, at 

 whatever period, and then perish : such De Candolle accordingly 

 designated as MONOCARPIC plants ; while to perennials, whether 

 herbaceous or woody, large or small, he applied the counterpart 

 name of POLYCARPIC plants, signifying that they bear fruit more 

 than once, or an indefinite number of times. Between herbs and 

 shrubs there are the intermediate gradations of 



160. Ullderslirubs, or suffruticose plants, which are woody plants 

 of humble stature, their stems rising little above the surface. If 

 less decidedly woody, they are suffrutescent. 



161. Shrubs are woody plants, with stems branched from or 

 near the ground, and less than five times the height of a man. Be- 



