56 NATURE TEACHING 



the roots spring from ; that the corm is gradually used 

 up and withers as the plant flowers and that a new 

 corm, which will flower next year, is formed on top of 

 the old one. Make careful drawings of (i) a corm ready 

 to plant, with its leaves on ; (2) the same cut through 

 lengthwise; (3) the same with the leaves stripped off; 

 (4) a plant in flower showing roots, etc. ; (5) a plant after 

 flowering, showing where the new corm arises. 



If the new corm is always formed on top of the old 

 one, why do not the corms after a few years appear 

 above the surface of the ground ? 



Examine plants of hop, bind-weed, and scarlet runner, 

 thin flexible stems about any convenient support. Make 

 out the direction in which the stem twines, and how the 

 free end of the stem moves in a circle until it meets with 

 some object to twine around. Make similar observations 

 on any other twining plants which can be obtained. 



Examine the cucumber, white bryony and grape vine, 

 and notice the special, delicate side branches tendrils 

 by which the plant clings to a support. Those of 

 the white bryony and cucumber usually twist up in a 

 beautiful manner, forming a spring, after they have 

 caught hold of an object, whilst before this they stick 

 straight out. Two examples only are mentioned here, 

 but many others will readily be found. 



Structure of Stems. 



Examine young and old pieces of the stems of any 

 of the following plants obtainable : elm, horse chestnut, 

 ash, oak, rose, hawthorn, and note, making careful draw- 

 ings, all the parts previously described (p. 46). Cut 



