This week the Gingko trees are at their peak along 46th Street near the Butler campus. Legend has it once the first leaf falls, all the others on a tree will fall within 24 hours. Ginkgos are popular urban street trees because of their columnar growth form (they usually have one main trunk with short side branches) and because they are tolerant of pollution.
Ginkgos are gymnosperms, the same plant group as conifers, pines and spruce etc. This group is considered more primitive than the flowering plants because their seeds are not produced within ovaries. The parallel vein patterns in the leaves are also considered primitive with in this group. The tree is sometimes given the common name maidenhair tree. You can use your imagination to figure out why.
Ginkgos, with their distinct leaf shape, were first known from the fossil record. They date back to the Jurassic, the time of the dinosaurs. They were rediscovered growing in remote mountain forests in China. They have been cultivated for centuries in Buddhist temple grounds. All our trees were derived from this seed stock.
Ginkgo is unusual in that it has separate sexes, male and female trees, and that the difference is due to chromosomal differences. Male trees are usually planted because the “fruit” of the female is stinky when it falls to the ground. I’ve heard it referred to as smelling like rancid butter. Where I saw “fruits” on the ground yesterday, if they had been stepped on, they smelled just like dog poop. Despite that unappealing notion, younger fruits are a component of Asian cuisine. I’ve seen cans of them in local markets.
The Latin name is Ginkgo biloba. The leaves are often notched into two lobes. The iconic leaf shape is a motif often used in jewelry.
This tree is the source of the supposed memory enhancing herbal treatment of the same name. From what I have read, it has shown some promise in delaying cognitive decline in folks with Alzheimer’s Disease but there is no evidence with will help college students cram for finals or me to find my car keys.