THE STEM. 13 



With respect to its general direction, the Stem is 



Erect or Upright, when it rises perpendicularly. 



Ascending or Oblique, having an oblique direction. 



Procumbent, lying on the ground. 



Creeping, running along the ground, and sending down roots 

 from space to space, in the manner of Fig. 2. The Runner 

 (Fig. 11.), is a stem of this kind, which, forming a bud at its ex- 

 tremity, produces a new plant, and then withers. 



Prostrate, lying remarkably flat. 



Clinging (Fig. 12.), holding fast to some other body for sup- 

 port, by means of fibres. 



Climbing, ascending on other bodies, either by fibres or by 

 tendrils. 



Twining round other plants or bodies. (Fig. 13.) Some stems 

 twine from left to right, others from right to left. 



Straight, proceeding in a direct course. 



Flexuous or Zig-zag, forming angles from right to left, and 

 the reverse. 



With respect to form, the Stem is 



Round or Cylindrical, when a transverse section is circular, or 

 nearly so. 



Semi-cylindrical, when flat on one side and round on the 

 other. 



Compressed, when more or less flat on both sides. 



Two-edged, when more or less compressed, with two opposite 

 sharp edges. 



Three-edged, or triangular, or three-cornered. 



Tour-edged, or four-cornered. 



five-cornered. When the number of corners exceeds five, the 

 stem is described as being angular or many-cornered. 



Winged, when the edges or corners are extended into thin 

 leafy borders. 



Jointed or articulated (Fig. 14.), when formed into distinct 

 parts united by portions of smaller diameter. 



