THE STI.M OF VASCULAR PLANTS. 137 



lenticels, or, very rarely, from the cicatrices of former 

 leaves, as I have observed in Seduvi altissimum ; the 

 origin of the roots which spring from the stems of her- 

 baceous plants has not yet been well determined. 



There are some plants in which all the branches or 

 stems are not equally capable of producing roots ; thus, 

 for example, the Strawberry shoots from the axils of its 

 lower leaves peculiar branches, which are called Runners, 

 (flagellcs, viticulce ; jets, coulans). These runners are 

 cylindrical, devoid of leaves in a part remarkable for its 

 length ; then their extremities produce roots, and thus 

 give origin to a bud of leaves : the runners or lower 

 branches of Lysimachia communis only differ from the 

 preceding in their not producing roots the first year, but 

 the following year both leaves and stems. The runners 

 of the House-leek differ only in the leaves being deve- 

 loped at the ends before the roots ; and on account of 

 their fleshy nature, which makes them reservoirs of 

 nourishment, may be separated from the another plant, 

 and then produce roots for themselves. 



Stems which, without being sufficiently strong to 

 stand up by themselves, are not prostrate upon the 

 ground, have a tendency to support themselves by 

 various means upon neighbouring bodies ; they are 

 generally said to be Climbing (grimpantes). This term 

 is applied indifferently to all the various modes by which 

 a stem can support itself upon another body — as, for 

 example, by means of cramps, as in the Ivy ; by tendrils, 

 as in the Pea ; by sending out long spreading branches, 

 as in Solandra; or by being provided with hooked 

 hairs, as in Galium aparine ; or by fixing themselves 

 by means of true roots, as in Ficus scandens, Ferns, 

 and climbing Orchideae ; or lastly, by twisting in a 

 regular spiral manner, as Convolvulus, &c. These last 

 bear the special name of Twining (volubiles) Stems, 



