The bees pollinated it :-)

Female trees are able to bear fruit (sterile/seedless) without benefit of a male tree to offer fertilization. I believe the technobotanical term for it is androdioecious.

Parthenogenesis. Not as much fun as thigmotropic, but not bad.

The species is not strictly dioecious...individuals may be polydamo-dioecious...when I untie my tongue i'll explain.

Alot of big words there!lol! Alright so there isn't something crazy going on here. Its just amazing how many sources say you need a pair (male and female) to get fruit.
Thanks for the info!

Here is but one from Horticulture magazine...

Fragrant spring flowers are very showy. Grows as a small tree or large shrub, often with more than one trunk, with a size that recommends it for a small garden or tight space. Dark blue fall fruit (female trees only) attracts birds. (A male and a female tree are needed for fruit set.)

whaas,
I, too, have a solitary C.virginicus that bears fruit, and I know that the next closest one is two miles away, as the crow flies. So...a male is not required; I don't have enough botanical expertise to determine if my tree is polygamodioecious, but I'm sure thinking so.

:(
I had 2plants (male and female seedlings, very lucky) male drowned one day. Actually, it only took an hour of the runoff flowing over the ground for the tree to die. It had been there 10 years, and we got one unreal downpour. Ditch overflowed, tree was killed.

Now I only have one female, and not a single fruit since. I'm planting another one next year, but I'm not sure if any nursery sells them sexed or not. I have American Persimmon that is self fruitful, and a Kentucky Coffee Tree that made beans for years as a single lonely tree. Why can't my Chionanthus be like them?

Quick-and-dirty definitions for those interested:

androdioecious - having male plants and hermaphroditic-flowering plants in the same species. (not sure of relevance in this thread)

parthenogenesis - production of unfertilized or misfertilized fruit that is often seedless or contains only infertile seed.

thigmotropic - movement or growth of a plant, in response to physical contact. (no relevance in this thread)

polydamo-dioecious - misspelling of polygamodioecious?

polygamodioecious - mostly dioecious (having separate male and female individuals) with a limited amount of bisexual flowers present.