European Hornbeam

These seed heads intrigue me. 

I found a tag on one of the trees, many on Arrowroot Loop. 

Carpinus betulus 'Fastigiata' (Pyramidal European Hornbeam) is a durable, slow-growing deciduous tree, ideal for formal hedges, privacy screens, or street plantings. It starts narrow/columnar and matures to a 30–40 ft tall, 20–30 ft wide, oval-vase shape. Known for its smooth gray, fluted bark and yellow fall color, it thrives in full sun to part shade and is highly tolerant of urban pollution.