KINDS OF STE3I AND BKANCUKS. 101 



roots, they may be made to grow independent!)-, drawing their 

 nourishment immediately from tlie 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 

 depends chiefly on the well-known fact, that buds propagate indi- 

 vidual jyecidiarities, which are commonly lost in raismg plants from 

 the seed. 



Sect. III. The Kinds of Stem and Branches. 



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

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

 and Trees. 



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

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

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

 perennial herbs has already been pointed out (144—146). 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 beai- fruit an 

 indefinite number of times. 



175. Uiulcrslirubs, or suffruticose plants, are woody plants of hum- 

 ble stature, their stems rising little above the surface. If less 

 decidedly woody, they are termed siiffrutescent. 



176. Shrubs are woody plants, with stems branched from or near 

 the ground, and less than five times the height of a man. Between 

 shrubs and trees there is every intermediate gradation. A shrub 

 which approaches a tree in size, or imitates it in aspect, is said to 

 be arborescent. 



177. Trees are woody plants with single trunks, which attain at 

 least five times the human stature. 



178. A Culm is a name applied to the peculiar jointed stem of 

 Grasses and Sedges, whether herbaceous, as in most Grasses, or 

 woody or arborescent, as in the Bamboo. 



179. A Caudex is a name usually appUed to a Palm-stem (Fig. 



9* 



