1. Arnold ML (1997) Natural hybridization and evolution. Oxford University Press, Oxford
2. Ayres DR, Ryan FJ, Grotkopp E, Bailey J, Gaskin J (2009) Tumbleweed (Salsola, section Kali) species and speciation in California. Biol Invasions 11:1175–1187
3. Baker HG (1965) Characteristics and modes of origins of weeds. In: Baker HG, Stebbins GL (eds) The genetics of colonizing species. Academic Press, New York, pp 147–172
4. Bennett FD, Crestana L, Habeck DH, Berti-Filho E (1990) Brazilian peppertree—prospects for biological control. In: Delfosse ES (ed) Proceedings of the VII International Symposium on biological control of weeds, pp 6–11
5. Blossey B, Nötzold R (1995) Evolution of increased competitive ability in invasive nonindigenous plants–a hypothesis. J Ecol 83:887–889