Cattleya walkeriana walkeriana" has been twice determined as 2"n" = 40; the diploid chromosome number of the variety "C. walkeriana" var. "princeps" has been determined as 2"n" = 80. Cattleya walkeriana Cattleya walkeriana (Walker's cattleya) is a species of orchid. It differs from most species of "Cattleya" by having inflorescences which arise from the rhizome instead of from the apex of the pseudobulb. In its native habitat (Brazilian Central Plateau) it grows as either an epiphyte or a lithophyte, sometimes in full sun. Pseudobulbs are relatively short, bulbous or fusiform, with one or two ovate leaves at the apex. Inflorescence is one-
Flowering Locus C produce a number of generations during one summer ("summer-annual"), or (b) flower only after vernalization ("winter-annual" or "late-flowering"). This kind of variation can also be provided by variation in the "FRIGIDA" ("FRI") gene. Flowering Locus C Flowering Locus C ("FLC") is a MADS-box gene that in late-flowering ecotypes of the plant "Arabidopsis thaliana" is responsible for vernalization. In a new seedling "FLC" is expressed, which prevents flowering. Upon exposure to cold, less "FLC" is expressed (to a degree depending on the amount of cold), and flowering becomes possible. "FLC" is extensively regulated through epigenetic modifications and transcriptional control. The expression