Diversity and adaptation of wild geophytes along an aridity gradient in Israel

Israel is known for its rich geophytic flora. Most geophytes are concentrated in the Mediterranean, transition and semidesert zones, while very few are found in the extreme desert. Biogeographical aspects such as endemism, speciation, phytogeographical affinities and vicarism are analyzed. Ecological analysis shows that most geophytes are found in open habitats and are rare in wet habitats, extreme dry habitats and closed shaded habitats. Charactersitics of the different geophytes are elucidated as their life history strategies. Results of resource allocation of two species (Allium stamineum and Scilla spp.) along the aridity gradient are analyzed and discussed. The results indicate that under minimum irrigation, desert populations drastically allocate their resources' from flowering to storage, while the Mediterranean population's tendency to do so is smaller. Vegetative reproduction was found to be stronger in desert populations of Allium stamineum, Tulipa systola and Urginea undulata, compared with the Mediterranean populations of Allium stamineum, Tulipa agenensis and Urginea maritima.