Above-ground emergence in the desert tulip Tulipa systola Stapf. in the Negev Desert of Israel

The number of plants appearing above ground during winter fluctuates from year to year. Between 10-70% of adult plants and between 40-80% of juveniles do not emerge in permanent quadrats in any year. Most reappear the following year. There is a significant positive correlation between the proportion of emergents in T. systola populations and the local amount of rainfall until 1 February. Early shoot development was independent of root development, but full root development was necessary for extension of the shoot to emerge above the soil. -from Author