Leaves are modified into hygroscopic appendages in
Tamarix
The primary function of the leaf is to carry out photosynthesis. It also carries out gaseous exchange through transpiration. Apart from these functions, leaves perform many other functions in different plants. It stores water in succulent plants like Aloe. It is modified into hygroscopic appendages in Tamarix. It is modified into bud scales stipules to protect buds in Ficus. Thus, the correct answer is 'Tamarix.'