Flowering affected by daylength and temperature in the leafless flowering desert geophyte Colchicum tunicatum, its annual life cycle and vegetative propagation

Colchicum tunicatum (Liliaceae) has an underground corm with three fleshy stalk internodes. The corm is replaced annually by a bud in the axil of the 1st foliage leaf. Sometimes the 2nd or 3rd axillary bud also develops into an independent shoot. Flowering takes place during autumn, before onset of rain, when leaves are still very small and positioned deep in the soil. At the time of leaf appearance during winter, the new replacement buds are visible on the newly developing corm. Corms. of C. tunicatum were planted 10 cm below the soil surface outdoors at Sede Boqer, Israel. Plants received 9, 12, 15, or 18 h light/day from sunlight, augmented with artificial low-level light after 4 pm. The shorter the daylength, the earlier flowering started, as long as the daily minimum soil temperature was >29°C. -from Authors