Quantitative aspects of the influence of day-length and temperature on Sedum telephium (Crassulaceae)

Under natural conditions the leafy shoots of Sedum telephium L. are strictly annual and produce only a single terminal inflorescence. The leafy shoots arise in early spring from the hibernating buds on a short, leafless sympodial rhizome with tuberous roots. The flowering shoots of S. telephium are monocarpic as in most perennial Sedum species. After the flowering period they die off, except for the lowermost, very short internodes which are added to the rhizome. According to Allard & Garner (1940), Von Denffer (1941) and Funke (1943) S. telephium is a typical long-day (LD) plant. Allard and Garner found that its leafy shoots require days of at least 17 hours to reach the flowering stage and in nature the plant will remain in a vegetative state up to approximately the 39th degree of latitude. Furthermore, they observed that the hibernating buds, which will give rise to next year leafy shoots, are formed more readily under short-day (SD) conditions (10-13 h).