These plants come from South China , Indonesia , Malaysia and the Philippines ; westward to Madagascar and the Seychelles ; southward to Australia and New Caledonia ; and northward to India and Sri Lanka . They are mostly liana-forming plants of the Old World tropics , ranging from South China , Indonesia , Malaysia and the Philippines ; westward to Madagascar ( 2 species ) and the Seychelles ( 1 ) ; southward to Australia ( 3 ) and New Caledonia ( 1 ) ; and northward to India ( 1 ) and Sri Lanka ( 1 ) .