72 STRUCTURAL BOTANT. 



213. Stems are either simple or branched. The simple stem 

 is produced by the unfolding of the primary bud (the plumule) 

 in the direction of its point alone. As this bud is developed 

 below into the lengthening stem, it is continually reproduced at 

 its summit, and so is always borne at the termination of the 

 stem. Hence the axis is always terminated by a bud. 



214. The Branched Stem, which is by far the most common, 

 is produced by the development of both terminal and axillary 

 buds. The axis produces a bud in the axil of its every leaf; that 

 is, at a point just above the origin of the leaf-stalk. These buds 

 remain inactive in the case of the simple stem, as the Mullein ; 

 but more generally are developed into leafy subdivisions of the 

 axis, and the stem thus becomes branched. A Branch is, there- 

 fore, a division of the axis produced by the development of an 

 axillary bud. This bud, also, ever renewed, is borne at the ter- 

 mination of the branch ; so that axillary buds, each in turn, 

 become terminal. 



215. The Arrangement of the Branches upon the stem, de- 

 pends, therefore, upon the arrangement of the leaves; which will 

 be more particularly noticed hereafter. This arrangement is 

 beautifully regular, according to established laws. In this place 

 we briefly notice three general modes. The Alternate arrange- 

 ment is where but one branch arises from each joint (node) on 

 different sides of the stem, as in the Elm. The Opposite is where 

 two branches stand on opposite sides of the same node, as in 

 Maple. The Verticillate is where three or more branches, equi- 

 distant, encircle the stem at each node, as in the Pine. 



216. Certain kinds of brandies are noted for their tendency to 

 produce adventitious roots, and thus to become independent 

 plants. Nurserymen avail themselves of this property in propa- 

 gation, and name such branches cions, suckers, stolons, offsets, 

 slips, layers, cuttings, and runners. The Sucker is a branch 

 issuing from some underground portion of the plant, leaf-bearing 

 above and sending out roots from its own base, becoming finally 

 a separate, independent plant. The Rose and Raspberry are 

 thus multiplied. 



217. The Stolon or Layer-is a branch issuing from some above- 

 ground portion of the stem, and afterward declining to the 



