Kentucky Coffee tree — Gymnocladus dioicus

Gymnocladus is from the Greek gymnos meaning naked and klados meaning branch. This refers to the fact that the soft, young wood is devoid of visible buds, thus making the tree appear dead in winter. The Latin dioicus refers to the sexual nature of the tree which is dioecious, meaning separate sexes.

When roasted the seeds are edible and were used by pioneers as a substitute for coffee. While not just a native of Kentucky, ranging from the Appalachians west to Colorado, this species adapts well to the better-drained, alkaline soils in Denver.

The vernacular name comes from the appearance of the seeds which resemble in size and color that of the tropical coffee. In winter, the stout, rather thick branches form a picturesque outline especially in silhouette. It is distinctive in mature bark which has thin, twisted ridges standing out at a wide angle from the surface of the trunk.

Other Denver locations

Washington Park on the east side, north of Mississippi along the park drive.

http://en.wikipedia.org/wiki/Kentucky_Coffee_Tree