Description: A tall tree with a straight, cylindrical trunk, light yellowish in color. Large trees have buttresses at the base, and these extend into roots that are visible above the ground as far as 30 m from the trunk. Wounds at the base of the trunk turn black from the sap exuded. Leaves are simple, alternate, and clustered toward the end of branches. They are heart-shaped, but the size and shape is quite variable. Large trees typically have some yellow leaves in the crown. The stipules of saplings are remarkable -- green and leaf like, but rolled into a little structure which ants sometimes inhabit (indeed, the stipule appears to be designed to house small creatures). In adults, the stipules are nothing like this and instead are thin and short.

Reproduction: Flowers are greenish or yellowish, small, produced in long stalks near the ends of the branches. There appear to be two flowering seasons per year, one in March and April, a second from August to October. The fruit is a small berry that turns purple when it is mature, either in May-June or November-January.

Distribution: Found from Gamboa to Sherman in the Canal area lowlands, but neither on the Pacific slope nor the wet forests of Santa Rita and the mountains. It is mostly a tree of forest edge or clearings in the forest; within the forest, there are scattered large trees but few saplings. Hyeronima is most abundant in Soberania, and there juveniles are common and readily seen along Pipeline Rd. Despite the edge preference, Hyeronima is not a tree of towns or open areas.

Similar Species: In juveniles, the bizarre stipules are a give-away, and these are easy to see at Pipeline Rd. In adults, Hyeronima is like several other Euphorbiaceae, with heart-shaped leaves that often turn yellow while still on the tree. In particular, see LK crotbi Croton billbergianus, LK2 and LK huracr Hura crepitans. LK2 Croton is also common along Pipeline Rd., and at a glance can be confused with Hyeronima, but Croton has small, stalked glands at the base of each leaf, and dying leaves in the crown are usually more orange rather than yellow. Hura has distinctly different leaf venation, and as a large treee it lacks buttresses. Several other Croton and Euphorbiaceae in the Canal area are restricted to remote wet sites.

Uses: Hyeronima had heavy wood useful in many kinds of construction, and it is well known in Central America and sometimes planted in plantations. Oils from the seeds are used medicinally as well as an anti-helminthic.