Sometimes field work gives us a reason to stop and look a little closer.
While tending to our Wellesley Garden project, our team noticed something interesting among two fringe trees growing on site. One had clusters of dark fruit, while the other did not. The difference asked us to take a closer look at what makes fringe trees unique.
White fringe tree (Chionanthus virginicus) is a small native tree in the olive family, Oleaceae, and is known for its distinctive spring flower. Its fragrant white blooms hang in long, loose clusters with narrow, strap-like petals, giving the tree its characteristic “fringed” appearance. The tree typically grows as a small, multi-stemmed tree or large shrub and is native to the eastern United Sates.
Fringe trees are generally dioecious, meaning male and female flower typically occur on separate trees. This is relatively uncommon among flowering plants, with only 5-6% of all flowering plant species considered dioecious. Both produce flowers, but the male flowers tend to be showier because of their longer petals. Female flowers can develop into clusters of dark bluish-black, olive-like fruit after pollination.
But fringe trees don’t always fit neatly into those categories. They can also produce perfect flowers, meaning a single flower contains both male and female reproductive structures. This means that they can present some variation beyond a straightforward male/female distinction. Some plants may even produce a small amount of fruit despite mainly functioning as male trees.
What started as a small observation in the field turned into a deeper look at the biology of fringe trees. It’s a good reminder that the plants we work with can surprise us, and that there’s always more to learn when we take the time to look closely.
Sources:
https://plants.ces.ncsu.edu/plants/chionanthus-virginicus/common-name/fringe-tree/
https://mortonarb.org/plant-and-protect/trees-and-plants/fringe-tree/
https://pubmed.ncbi.nlm.nih.gov/25326608