324 REPRODUCTION 



Compare the leaves and flowers formed on grafts with those on the 

 plant from which they were taken. After union of scion and 

 stock has been accomplished cut transverse and longitudinal sec- 

 tions of the united portions and ascertain the method of union of 

 the tissuesof the scion and stock. 



It will be profitable also to make grafts with such woody plants 

 as the apple, rose, and other convenient species. 



421. Propagation by Buds Formed on Leaves. A discussion 

 of buds formed on leaves of various ferns has been given in a 

 previous section. A large number of seed plants are found to 

 bear buds on leaves, among which are Nasturtium officinale, and 

 Cardamine pratensis. Still a larger number are capable of de- 

 veloping buds, when mutilated or separated from the shoot. This 

 capacity is widely prevalent among succulents. 



422. Leaves of Begonia. Cut off a separate leaf of any convenient 

 species of Begonia, or of Bryophyllum and press down on sand in 

 moist chamber. Cut another leaf into fragments and insert the 

 edges in the sand. Note the formation of buds and the manner 

 in which new plants arise. Repeat with any succulent plant. 



423. Formation of Tubers and Plants by Leaves of Gloxinia. 

 Cut vigorous leaves of Gloxinia from the stem and insert the 

 petiole deeply in moist sand under a bell-jar. Note the forma- 

 tion of roots from the leaf cutting and the development of a tuber. 

 Follow the course of the leaf; does it form a part of the new 

 plant ? Repeat with leaves of Boussingaltia baselloides (Fig. 1 58). 1 



424. Propagation of Apios tuberosa. Make cuttings from 

 vines of Apios which shall include a leaf and a short section of 

 stem to which the petiole is attached. Imbed the stem and base 

 of the petiole in moist sand and cover with a bell-glass. Note 

 the course of growth of the new individual : are juvenile leaf 

 forms to be seen ? 



425. Propagation by Flowering Branches. The replacement of 

 flowering branches by propagative buds is exhibited by a number 

 of alpine forms inclusive of Poa alpina, Poa bulbosa, and various 



1 Vochting, H. Physiologic der Knollengewachse. Jahrb. Wiss. Bot. 24 : 54. 1899. 



