The two Sumatran wild bananas, Musa acuminata subsp. halabanensis and M. salaccensis, belonging to the different sections Musa and Callimusa respectively, have contrasting flowering traits corresponding to their different pollination syndromes: i.e., chiropterophily and ornithophily, respectively The M. a. halabanensis flowers, on pendent inflorescences with dark purple bracts, produced jelly-like nectar of 22-25 percent sugar concentration primarily at night, and were pollinated by the nectarivorous pteropodid bats, Macroglossus sobrinus. In contrast, the M. salaccensis flowers, on erect inflorescences with purplish pink bracts, produced dilute nectar of 18-21 percent sugar concentration primarily in the daytime, and were pollinated by the nectarivorous nectariniid birds. Arachnothera longirostris and Aethopyga siparaja. The flowering span of each female flower was 24-40 hr, while that of the male flowers was < 12 hr. Open flowers of both species contained significantly less outcrop of nectar than bagged flowers. Fruit weight and seedset of open M. salaccensis flowers were significantly more than those of bagged flowers and were significantly less than those of hand-pollinated flowers.