Imagine not seeing your closest living relative for ten or fifteen million (yes million) years. And on top of that, you and your closest living relative end up on different continents. So much time, so much opportunity for evolutionary divergence. The two extant species of tulip trees, Liriodendron tulipifera (eastern North America) and Liriodendron chinense (eastern and central China) have been reunited on the grounds of the Arnold Arboretum. Amazingly, these species are still interfertile and several of the hybrids (Liriodendron tulipifera x chinense) can be found growing in what certainly can be viewed as a true family reunion, just a hundred yards from the Hunnewell Building.

The flowers on these hybrid tulip trees are stunning and display bright chevrons of orange color (characteristic of the American parent). Below, a just opening (upper left) and newly opened (upper right) flower in female phase (147-2000*A). Like most members of the magnolia family, each of the hermaphrodite flowers is “protogynous” (female first)—the stigmas receive pollen (from other flowers) first, and then pollen is released from the elongate flattened stamens. In flowers that have been open for a few days (and are in male phase), the stigmas sticking out of the conical central structure (receptacle) are dried up and brown (lower left). Lower right, one of the flowers wonderfully lit up by the sun.

flowers of hybrid tulip tree by Ned Friedman