The spiny, thorny and prickly plants in the flora of Israel

Abstract

To examine whether spininess evolved at random or differently in various life forms and plant organs, we characterized spiny, thorny and prickly organs in the entire wild flora of Israel (294 such species). Of the species, 63.3% defended their reproductive organs (the most-defended organ) and 67.0% defended various non-reproductive organs. Ninety-three species defended both their reproductive organs and at least one other part; 48.3% defended their leaves and 36.4% their stems and branches. Spiny wings defended stems and branches only in herbaceous (annual or perennial) species. There were clear differences between the life forms. Annuals and perennial herbs defended mostly their reproductive organs (95.7 and 83.0%, respectively), dwarf shrubs defended mostly their leaves (54.2%) and shrubs and trees mostly their branches (89.7 and 76.2%, respectively). Trees do not defend their reproductive organs by associated sharp appendages. The differences in defence on various organs among different life forms may influence the results of meta-analysis studies of the optimal defence allocation if such differences are not taken into account. We noted spine, thorn and prickle colours for 167 species with yellow, red, orange and white being the dominant, supporting hypotheses about spines being visually aposematic. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168, 344–352.