Styrax paralleloneurus (syn. Styrax sumatranus) is a species of Styrax native to Sumatra and Peninsular Malaysia. It is the main source of benzoin in Sumatra. Its balsamicresin is superior to that of Styrax benzoin, another source of benzoin Sumatra, as the latter dries slowly and remains sticky, hence more inpurities. It can have the largest galls of any known plant; up to 20cm long, and about half as wide.
↑Katz, Esther; García-Fernández, Carmen; Goloubinoff, Marina (2002). "Sumatra benzoin (Styrax spp.)". In Shanley, Patricia; Pierce, Alan R.; Laird, Sarah A.; Guillén, Abraham (eds.). Tapping the Green Market: Certification and Management of Non-Timber Forest Products. People and Plants Conservation Series. London; Sterling, VA: Earthscan. p.251. ISBN978-1-85383-871-2.