THE STEM 55 



Place a ripe artichoke to germinate. Notice where 

 the new shoots come from. Notice carefully how, on 

 the new shoots, there is a gradual transition between 

 the scale leaves of the tuber and the ordinary green 

 leaves of the plant. Draw some of the best instances 

 to show this. 



Dig up carefully a potato plant, when the potatoes 

 are about half-grown, and wash it clean from soil under 

 a tap. Examine the underground stems on which the 

 potatoes are borne, looking especially for any small 

 leaves distinguishing them from the roots. Make draw- 

 ings. Notice the "eyes" in the potatoes. Get some 

 seed potatoes and place them in damp sand until they 

 begin to sprout, and ascertain whether the new shoots arise 

 anywhere on the potato, or from the eyes only. Make a 

 drawing of a potato before it has started sprouting, 

 showing the eyes ; and after it has sprouted, showing the 

 young shoots. 



Obtain some crocus corrris. Gladioli are still better, 

 being larger, but they are more expensive. Notice the 

 dry scale leaves forming a protective covering, and the 

 white pointed buds at the top. Pull off the scale leaves 

 one by one, and compare the scars they leave with those 

 already seen in the iris. Cut the corm through length- 

 wise ; it is solid. It is thus a stem structure, bearing 

 leaves (the brown scales) at definite places (nodes), and 

 is in reality a very much swollen stem. With the 

 help of a lens, it is possible to see the young leaves and 

 the flower, packed away in the central bud, when it is 

 cut through. Dig up crocus plants (i) when in flower, 

 and (2) after the flowers have died. Make out where 



