Ill 



ANATOMY-STUDY OF THE SHOOT 



plant. The so-called eyes that are found on the outside of a 



potato are in reality buds, from which the next year's growth 



will take place. The parent plant 



dies after the production of tubers, 



but not before large stores of reserve 



materials have been accumulated in 



the tubers for future use. If the 



aerial branches of the Potato plant be 



covered up with soil, their growth 



will be checked and they will produce 



tubers. The Jerusalem Artichoke and 



the Earth-nut also produce tubers. 



The Bulb is a modified stem often 

 met with in monocotyledonous plants. 

 It consists of a short thickened stem 

 with a large number of crowded, over- 

 lapping leaves. These leaves contain 

 a large quantity of reserve material 

 for the growth of the next season's 

 plant. In the Onion the leaves 

 sheathe one another, but in the Tiger 

 Lily they only overlap. The bulb is 

 closely allied to the tuber. The 

 Onion, Wild Hyacinth, and Daffodil 

 are examples of plants that produce 



bulbs. 



The Corm is a 



very solid fleshy 



stem with fewer 



leaves than che bulb. In the Crocus it is a 



solid, rounded, main axis, full of reserve 



materials. The Snowdrop and Gladiolus 



spring from corms. 



EXPT. ii. Obtain from a gardener a piece 



of the runner of a Strawberry plant. Note 

 r IG. 21. Corm of / - \ tr it. re 



Crocus. w H w the runner gives off roots. 



(ii) How the leaves are produced. The leaves 

 are developed from the upper surface of the 



stem and from the nodes 5- the roots spring from the lower surface 

 of the stem. 



k 



zk 



FIG. 20. Longitudinal section 

 of bulb of Tulip, zk, modi- 

 fled stem ; zs, scale leaves ; 

 57, terminal bud ; k, young 

 bud ; w, roots. 



