The world important food crop—cultivated rice (Oryza sativa
)—is domesticated from its wild ancestor (O. rufipogon
, A). Cultivated rice has differentiated into indica subspecies (O. sativa
, C) and japonica subspecies (O. sativa
, D), adapting to tropical and temperate regions. Weedy rice (O. sativa
, B) is morphologically between the wild and cultivated rice and has close relationships with them. Photographed by Bao-Rong LU. See LIU et al., pp. 1–11 in this issue.