For three centuries the treatise De plantis has been poorly represented by a Byzantine Greek translation of a mediocre Latin version made from the Arabic, which in its turn came from a Syriac rendering of the lost original. Since this Byzantine version was four times removed from the Greek exemplar, its authority was, to say the least, questionable. However, it was printed in 1539, and in spite of ubiquitous disapproval found its way into all subsequent editions of the Corpus Aristotelicum. In the present book the fragments of the Syriac version and the text of the four other translations (Arabic, Latin, Greek, Hebrew) are edited afresh. As far as possible, the manuscriptal evidence is complete, and each text is provided with an introduction and copious notes concerning philological problems. A few of the numerous commentaries are added and the vexed question of whether Averroes had written a commentary on De plantis is treated at some length.