罂粟科在区系地理上属于典型的北温带分布科。因此，它是研究北半球不同植物区系相联系历史的理想关键类群。在已有研究的基础上，本项目拟选取罂粟科植物约300种，代表了该科全部42属并覆盖每一属的分布区，利用9个DNA片段和形态性状重建罂粟科植物的系统发育树；整合系统发育、性状进化、分化时间和生物地理等分析方法，探讨限制祖先分布区数目对其生物地理推断的影响，揭示罂粟科植物时空演化的格局及其成因。通过本项目研究，将会加深人们对罂粟科植物进化历史和北半球不同植物区系间渊源的理解，也会为其他类群生物地理学的深入研究提供借鉴和参考。

Papaveraceae is a typical family in the north temperate zone on the floristic geography. The family is therefore a key taxon to study the floristic origin and evolution within the Northern Hemisphere. In this proposal, we will use a greatly enlarged taxon sampling (ca. 300 species, representing all currently recognized 42 genera of the family and covering the geographic ranges of each genus). Based on morphology in combination with nine DNA sequence data, including plastid rbcL, atpB, matK, ndhF, trnL-F, rps16, and trnG, and nuclear ITS and 26S rDNA, we will first reconstruct a robust phylogenetic framework for Papaveraceae. By an integration of phylogenetic, character evolution, molecular dating, and biogeographic methods, we will then explore the potential effect of constraining maxareas on biogeographic inferences, investigate the temporal and spatial evolution patterns of the family on a worldwide basis, and consequently elucidate how the biogeographical links among different floristic regions within the Northern Hemisphere have been established. By this proposal, we will provide new insights into the origin and evolution of the floras of the Northern Hemisphere.