Ch. Ill, 8] FORMS OF FOLIAGE LEAVES 



71 



A very remarkable form of leaf occurs in the Welwitschia 

 mirabilis of Southwest Africa, a plant unique in a great many 



Fig. 42. — Welwitschia (Tumboa) mirabilis, growing in the desert of Kala- 

 hari, Africa. The woody trunk, though many years old, is but two feet in 

 height. (From Kerner.) 



features (Fig. 42). The leaves, only two in number, grow 

 at their bases as they die at their tips throughout the long 

 life of the plant. 



Leaves are pro- 

 duced in buds, but 

 produce buds in very 

 few cases. The leaves 

 of some kinds of Be- 

 gonia, however, if cut 

 across the veins, de- 

 velop buds which 

 grow into normal new 

 plants ; and gardeners 

 are accustomed to 

 propagate those Be- 

 gonias in that way. In 

 the well-known Life 

 Plant (liryophyllum), 

 the rather thick fleshy leaves regularly produce buds at the 

 outer ends of the veins (Fig. 13) j and these buds develop 

 freely into young plants when the leaves fall on damp soil, 



Fia. 43. — The Life Plant (Bryophyllum 

 calycinum), developing young plants on the 

 margin of the leaves ; X J. (From Kerner.) 



