Most floral nectar proteins (nectarins) are reported to function in nectar defence, particularly for insect-pollinated outcrossing species. Zha et al. compare nectarin composition in selfing common tobacco (CT; Nicotiana tobaccum) to outcrossing ornamental tobacco plants and find that the most abundant nectarin in CT nectar is an acidic alpha-galactosidase that has not been detected in the nectar of outcrossing sister species. CT fruits do not develop intact skin with galactose inhibition of a-Gal activity in the nectar. The results indicate that floral nectarins in selfing species maintain their functional significance in reproductive organ development.