ii. MORPHOLOGY 



the roots of patal (Trichosanthes dioicd) produce Such 

 buds, and the plants are usually propagated by cultiva- 

 tion from them. Similarly, the leaves of pathar-kucha 

 {Bryophyllurii) (see fig. 1 26) and him-sagar {Kalanchoe) 

 give rise from their margin to adventitious buds which 

 grow into plantlets. Truncated trees are often seen 

 to put forth new shoots, and these shoots mostly 

 spring from adventitious and dormant buds. Date- 

 palms are usually branchless, but occasionally they 

 are found with two or more heads, and these heads 

 are due to the growth of dormant axillary buds. 

 Normally only one bud is produced in the axil of each 

 leaf, and the production of more than one bud from 

 the same leaf-axil may be taken as exceptional. 



Although the majority of plants develop their stems 

 in air, there are some in which the stems live and 

 grow upder the ground, and are therefore popularly 

 mistaken for roots. But, like aerial stems, they are 

 provided with leaves and buds, and have all the mor- 

 phological characters of a stem, though they may look 

 like roots and have root-like environment. The leaved 

 of these underground stems are never green, like 

 ordinary leaves, and are often very small ; hence they 

 are known as scale leaves, or simply scales. The 

 buds in the axils of these scales usually give rise to 

 annual aerial, shoots which unfold green leaves, put 

 forth flowers, fruits, and seeds, and then die down to 

 the ground, leaving the perennial underground stem to 

 grow under the ground and repeat year after year the 

 production of aerial annual shoots, &Gj Such under- 

 ground stems or their scales are usually thick and 

 swollen, with an abundant store of nutrient materials 

 which serve to feed the annual shoots described above. 

 Plants with underground stems are therefore usually 

 propagS-ted in cultivation not from seeds but from 



