228 Tall Bearded Iris 



branches attached; plunge them in the garden and 

 leave the plants to bloom and make their growth in 

 the pot, watering and feeding them during the growing 

 season; after the plants have had a freeze and severe 

 weather comes on lift the pots, and then give them 

 substantially the treatment set out above. 



Some leave the plants in the garden until the ground 

 is frozen, lift and pot them during the first winter- 

 thaw, and then bring them in. 



Heretofore the explanation of necessity for freezing 

 has usually been, that the plant must have some period 

 of practically complete rest before it can flower again, 

 and that this is brought about by freezing. Of late 

 the theory has been advanced by some scientists, 

 that the new growth does not begin until some of the 

 starch stored in the cells of the plant has been turned 

 to sugar; the enzyme that converts the starch to sugar 

 is supposed to exist outside the plant cells and to be 

 unable to penetrate into them until the cell wall has 

 been weakened in some way, as by freezing.* 



Even while the plants are not in bloom they are a 

 welcome addition to the living room. Their bright 

 green leaves are cheery. Each new leaf growing for 

 inches inside an older one (see under Foliage, page 123, 

 Flower-Stem, page 126) its outline plainly distinguish- 

 able through the latter when the plant is in the light- 

 then gradually emerging, is almost as interesting a 

 sight as a flower unfolding, and its emerging will be 

 eagerly watched 



*American Botanist, February, 1922. 



