The Collaborative International Dictionary of English v.0.48:

Sola \So"la\, n. [Native name.] (Bot.)
   A leguminous plant (Aeschynomene aspera) growing in moist
   places in Southern India and the East Indies. Its pithlike
   stem is used for making hats, swimming-jackets, etc. [Written
   also solah, shola.]
   [1913 Webster]