The wandering carpel mutation of Zea mays (Gramineae) causes misorientation and loss of zygomorphy in flowers and two-seeded kernels.

We have isolated a new mutation, wandering carpel (wcr), which affects polarity of the maize flower, altering its orientation or converting it from zygomorphy to radial symmetry. These changes result in the development of embryos on locations other than the normal, acropetal side of the kernel. More than two carpels can develop into silks. More rarely, two ovules develop in a single ovary, giving rise to kernels with two seeds. The wcr mutation is a maternal-sporophyte-effect, semidominant mutation whose expression is background dependent. As spikelets with abnormal flowers are almost always paired with a normal spikelet, we hypothesize that WCR+ is required for establishing polarity in spikelet meristems during inflorescence development.