22 



ORGANOGRAPHY. 



square stems (Fig 10). Some plants, as the Wire-Grass 



(Poa eompressa, L.), have flattened stems (Fig. 11) ; others 

 may be winged (Fig. 12). Those of 

 Grasses and Sedges are conspicuously 

 jointed and sometimes hollow, and have 

 received the special name of culm (Fig. 

 13). The trunk of the Palms, and the 

 like, is-called caudex. 



20. Certain forms of branches are used 

 by gardeners for the purpose of propa- 

 gating by buds. Such are Suckers, 

 Stolons, Offsets, and Runners. Suckers 

 arise from underground 

 stems. Stolons are 

 trailing or reclining 

 branches which take 

 13 root where they touch 



the soil. Offsets are short Stolons, like 



those of the House-leek. Runners are 



slender, leafless creeping branches, which, 



when the full length is attained, take root 



at the tip, form a bud, and develop an 



independent plant. 



21. Some tendrils are slender branches 



destitute of leaves and intended for assist- 

 ance in climbing. Examples are furnished 



by the Grape- Vine, Virginia Creeper, 



Squash, etc. (Fig. 14). They generally 



grow out straight until some slender 



object is reached, around which the tips 



Fig. 13. Culni or stem of Grass, Fig. 14. Tendril (t) of the Wild Balsam-apple 

 {Echinocj/stis), attached at the tip and coiled to the right f^r) and to the left (/). 



