V EG ETA TIVE REP ROD UCTION. 



267 



Some species of Kleinia, natives of Cape Colony, have fleshy 

 stems, jointed at intervals, so that they easily break there. 

 When broken off by an accident, the piece rolls away, takes 

 root from the under side, and sends up shoots from the upper. 



Advantage is taken of this power of severed parts to form 

 adventitious roots and shoots in the artificial propagation of 

 domestic plants. Suitable portions of shoots or leaves for 

 the development of new plants under proper conditions are 

 called cuttings, scions, or "buds." They may generally be 

 grown in water or soil ; or they may be securely fastened in 

 a slit or wound in another plant. The latter process is 

 known as grafting or budding, according to the form of the 

 implanted part. Indeed br^od buds in general may be 

 looked upon as natural cuttings or scions. 



368. Branching. — A further modification of this method 

 of reproduction is to be ob- 

 served in the formation of 

 new individuals through pro- 

 gressive death of the older 

 parts. If a plant, dying thus, 

 be a branching one, death will 

 sever the branches as it reaches 

 them sooner or later, and 

 each branch then becomes an 

 independent plant. This is 

 seen in its simplest form in 

 those plants which have a hori- 

 zontal branching thallus whose D 

 base dies as the apex elongates Fig. 300.— Outline of a thallus of Mar. 



. chant ia geminata. The base D is 



(fig. 300). It IS COmmOll 111 dying as the apices are growing and 



branching. When death reaches the 

 plants With Underground Creep- first fork there will be two independent 



plants ; at the second there will be four, 



ing stems which send up aerial and so on. 



leaves or shoots annually, as do the ferns of temperate regions 



and many grasses and mints. 



