DISJUNCT DISTRIBUTIONS IN THE NEW WORLD ZYGOPHYLLACEAE

Abstract

Summary The disjunction of the genus Larrea between the arid regions of North and South America is well known and much discussed in the phytogeographical literature. Not so well known are the North American‐South American disjunctions in Fagonia and Porlieria , the New World‐Old World disjunctions in Fagonia and Peganum , and Bulnesia's disjunction within South America. Each genus, its close relatives in the family, and possible explanations for its present distribution are discussed.