GRAFTS 



321 



of the bulbil ? Are juvenile leaf-forms produced ? Examine 

 the scales and epidermis of the bulbil. The bulbil will be found 

 to complete its arrested development as a stem, becoming the 

 rhizome or main axis of the new plant 1 (See Figs. 151-154). 



417. Reproduction of Lilium by Bulbils. Note the formation of 

 bulbils in the axils of some of the species of Lilium. Germinate 

 and note fate during the process. Dissect and ascertain the loca- 

 tion of the growing points. What is the character of the storage 

 material ? Test endurance of the bulbils to desiccation, cold, 

 heat, and chemicals. 



418. Reproduction of Aquatic Plants by Buds. Observe the 

 death of plants of Utricularia, Philotria, and Potamogeton grow- 

 ing in ponds or lakes in the autumn. The terminal buds are 

 seen to be densely clothed with leaves forming a more or less 

 compact mass that sinks to the bottom after the death of the 

 main stem. Secure a number of such buds and place in an 

 aquarium in a temperate house. Note manner of growth and 

 fate of buds. Here as in Lysimachia the bud will be found to 

 form part of the new plant (Fig. 155). 



419. Grafts. Grafting is a special method of propagating cut- 

 tings much used in horticultural practice for the multiplication 

 and preservation of special varieties of plants with woody stems. 

 It may also be used with herbaceous plants, although but little 

 practical advantage is to be gained from it. It consists essen- 

 tially in attaching a cutting containing one or more buds, to the 

 root or stem of another plant in such manner that both the cgt- 

 ting and the stock on which it is placed form a callus, which unites 

 and develop a series of connecting tissues correspondent to those 

 of the stock and scion as the cutting is generally termed. After 

 the two are united the buds of the stock are generally sup- 

 pressed in practice, and the crown of the plant will be composed 

 of the branches developed from the scion, although it is possible 

 to unite a number of the cions of different kinds to a stock and 



1 MacDougal. Vegetative propagation of Lysimachia terrest) is. Bull. N. Y. Bot. 

 Gar. 2 : No. 6. 1901. 



22 



