Well, my best guess would be that it is okay rather than wonderful. At least it blooms here when there is nothing else is in bloom, and it has showy seeds, more so than the blooms. Some would consider it an invasive exotic.

lol ken ... what is it ,....ken, the other one ...

Ken, if the OP is in a temperate zone, it's probably Koelreuteria bipinnata, hardy to zone 6-7. If in the subtropics, probably K. elegans (formosana) hardy to zone 9. Both species are almost identical except for hardiness. I grow the former, both are called goldenrain.

Hi thanks to BOTH Ken's :) Never would have suspected Golden rain tree. Here in 10-ish coastal so. Ca., some do say invasive. Dug up from a small courtyard with only nearby being some type Japanese Maple, and other ( yuk) Brazilian Pepper. Guess a bird dropped it, but my digger( husband) swears it came off of a root.

Oh shoot! Partial comment from So. Living "....I feel like a eco-terrorist, like the first remorseless clown who sicced Japanese honeysuckle, privet, water hyacinths, dandelions, and crabgrass on America. Long after I am gone, people in Alabama will point to the 12 Chinese flame trees that just sprouted in their petunias and curse my name.”It was Bender!”

DON’T PLANT CHINESE FLAME TREE, NO MATTER HOW PRETTY IT LOOKS! "

What are the features that make it K bipinnata and not K paniculata?

Twice compound leaves.

K paniculata has both pinnate and bipinnate leaves. I've only ever seen K paniculata and am trying to get a handle on the differences. On line images are not very helpful. This siteshows a very distinctively bipinnate leaf for bipinnata which doesn't look much like the OP's foliage. Whereas this site shows bipinnate leaves for paniculata which do seem more like the OP's.

I've grown Kp for years, got lots of volunteers, and it is a very commonly planted here. I've never seen twice pinnate leaves, only pinnate.

As far as actual differences between the species in question, Kp blooms in May/June with yellow panicles and produces tan bladder-like structures that enclose a hard black seed. The seed panicles quickly turn a ratty brown. The trees grow to about 8M/30F, with a rounded crown. There is usually little fall color, sometimes yellowish. The trees don't live particularly long, and don't age well.

Kb and Ke bloom in Aug/Sept and into Nov for Ke. The flower and seed panicles are near double the size of Kp yellow for blooms, and BRIGHT rose red for seed structures, which are far and away more ornamental than the blooms. Seeds and blooms are usually present together, as these species have a longer bloom period than does Kp. Tree shape is rounded upright. Kb grows to 11M/40F, Ke18M/60F. Both species have fairly large twice pinnate foliage which looks somewhat tropical/lush. Both species live considerably longer than Kp, and look better in old age. Both have no fall color and leaves fall greenish or brown if frozen. Hardiness mentioned above.

Edited to remove blanket 'invasive exotic' statement.

Kb and Ke love hot weather, Kp does well in areas with cooler summers.

"All species are considered invasive exotics in most of the US."

That's not true at all. In very few locations is Koelreuteria considered an invasive species. Growing them in cooler climates generally significantly limits seed production. Grew one for almost 30 years in my old garden and never a sign of any seedlings. Foliage looks exactly like what is shown - semi-bipinnate :-)

Neither species is considered invasive in SoCal and are even recommended plantings in much of the state.

This site has it listed in San Bernardino, L.A., San Diego & Riverside counties.

While the late blooming one is a welcome site at that time of year OMG what a seedling headache. I don't grow, plant or recommend raintree in Maryland.

That site only reports where the species has been found....not where it is considered invasive. It is NOT on any of the official California Invasive Species lists.

In my experience, K. paniculata is barely bipinnate while K. bipinnata is consistently and strongly bipinnate.

Based on OP's location, I'd agree with kentrees that it's likely K bipinnata.

But see also this publication http://www.hort.cornell.edu/uhi/research/articles/LandPlantNews17(2).pdf

which says of K. paniculata (see pages 8-9, especially pic on p.9) "Variation in leaf morphology alone is tremendous, with some Chinese provenances sharply dissected and bipinnate (yet distinct from Koelreuteria bipinnata) compared to the typically pinnately-compound leaves."

Not a common tree here at all, in fact, I have only seen one. Beautiful trees, but if you don't have a place to plant it you could turn it into a bonsai.

Hmm, the golden rain trees around here seem to all have bi-pinnate leaves.