Virescent Chilicothe [Marah macrocarpus (Greene) Greene]

I photographed the virescent and normal forms of Chilicothe in the Spring at Casper's Wilderness Park in southern California. When I returned a few months later, there was no sign of the virescent form or any dead vines. This may be an instance of temperature dependent virescence like the mutant maize characterized by E. S. Robertson and I. C. Anderson in 1961. In that case homozygotes were normal green at 37°C but virescent at 20°C.

The double flowered Stocks (Matthiola incana) is another example. When the seedlings are grown at low temperatures some will turn pale. Only these will bear double flowers because the "gene" for virescence is linked to that for doubling.

Other examples were described by Alberte et al. (1974) in maize, soybeans and cotton.