ABSTRACT
C. Medium L. is a popular biennial garden plant. It has quite remarkable flowering requirements, because not only does it initiate its flowers after vernalization, but also after short day followed by long day at ordinary greenhouse temperatures. The actions of cold and short day are quite different although their final effect is the same, i.e., flower formation, but it is not known whether the same floral hormone is responsible for this effect. All in all, the C. medium research has yielded interesting ecological reactions which, however, do not allow us to draw conclusions regarding their physiological backgrounds. Unfortunately, for several technical reasons C. medium is not an attractive plant for experimental purposes. Wellensiek reported that Gibberellic acid had a strong stem-elongating effect without flower formation. When control plants and Gibberellic acid-treated plants with elongated stems were vernalized, they flowered simultaneously in long day following the cold-treatment. Hence stem elongation and flower formation are completely independent processes.
