Garden News Blog

The Living Lineage of Flowering Plants

Amborella trichopoda (Amborellaceae) is the earliest known living lineage of flowering plants. Any student who has taken a class with me over the last 10 years has learned about this amazing plant. In its endemic country of New Caledonia, on Mt. Aoupinie, I finally got to see this amazing and very strange flowering tree.

The two earliest known lineages of flowering plants—that is, the earliest known branches in their evolutionary tree—are Amborella trichopoda and the order containing water lilies (Nymphaeales). What makes this finding so odd is that these two lineages are extremely different in their external and internal structure. Amborella is a small woody tree with very structurally reduced flowers and separate male and female individuals (i.e. it’s dioecious); whereas, water lilies are aquatic herbaceous plants with very complex flower structure and individuals have flowers containing both female and male reproductive parts (i.e., they are hermaphrodite).

In addition, unlike the vast majority of flowering plants, including water lilies, Amborella has no vessel elements through which to transport water. Seeing this plant sterile would have been an amazing experience, but we got to see it in flower (both female and male trees) and fruit (only female trees make fruit because fruits develop from the ovary, part of the female reproductive organ)!!

Susan Pell is the director of science at BBG, where she studies the evolutionary relationships of the cashew family. She holds a PhD in plant biology and teaches continuing education and training courses in genetics, angiosperm morphology, and systematics.

Image, top:
Leaves and female flowers of Amborella trichopoda. Photo by Susan Pell.
Female (right 2) and male (left 1) flowers of Amborella trichopoda. Photo by Susan Pell.
Fruit of Amborella trichopoda. Photo by Susan Pell.