Their ancestors were parasitic on ancestors of some plants of Loranthaceae by chance during Tertiary. It took them millions of years to form a sturdy relationship between parasites and hosts.
在第三纪，重寄生属植物的祖先偶然寄生在桑寄生科某些植物上，经过几千万年的协同进化，形成了今天比较稳定的寄生与寄主关系。
参考来源 - 硬序重寄生（Phacellaria rigidula Benth.）及其寄主协同进化的初步研究