1. Polyploidy and self-fertilization in flowering plants
2. Polyploidy in arctic plants
3. Asynchronous expression of duplicate genes in angiosperms may cause apomixis, bispory, tetraspory, and polyembryony
4. Commission for Environmental Cooperation (1997). Ecological Regions of North America: Toward a Common Perspective. Commission for Environmental Cooperation, Montreal, Quebec, Canada.
5. Crataegus Species—The Hawthorns (2021). https://pfaf.org/user/cmspage.aspx?pageid=59#:~:text=Once%20established%20
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