There are two katsuras in the Park, a female in the east triangle and a male in the southeast triangle. See Wikipedia entry here.
Cercidiphyllum is a genus containing two species of plants, both commonly called katsuras. They are the sole members of the monotypic family Cercidiphyllaceae. The genus is native to Japan and China.
Female katsura in the east triangle in July
Katsuras are dioecious, meaning that some individual trees have male flowers and some have female flowers. Only the female trees have seed pods.
As the scientific name suggests, these trees are from east Asia.
The scientific genus name, cercidiphyllum, means having a leaf like the genus Cercis, the redbuds. Compare the katsuras with the numerous redbuds in the Park. Redbud leaves are alternate, not opposite on the stem.
The leaves have a strong scent in the autumn, sweet like cotton candy or burnt sugar.
The leaves turn yellow-orange in autumn
The seed pods look like tiny clusters of bananas along the branch, and the seeds are released in late autumn or winter
The largest tree in all of Philadelphia is a katsura at the Morris Arboretum
Female katsura in the east triangle with seed pods along branch
Note heart-shaped leaves with edge striations. July photo.
Male katsura (no seed pods) in the southeast triangle in July photo
A katsura branchlet with leaves and seed pods in the middle, flanked by branchlets from two different redbuds with their corresponding seed pods. Though all the leaves are heart-shaped, the redbud leaves alternate on the branchlet and have longer stems.
Note the purple color of both leaves and seed pods from the redbud on the right, which is from the only redbud in the west triangle. Photo taken in July.
Summary of the physical characteristics of the katsura tree
Female katsura in November, without leaves but covered with thousands of mature brown seed pods
One of the thousands of banana-like seed pods in November, with the contents of another seed pod: about two dozen tiny winged seeds.
There are two katsura species: C. japonicum has seeds winged only at one end, as seen here. C. magnificum has seeds winged at both ends.