This rare Caribbean shrub is the Tropical Lilythorn, Catesbaea melanocarpa.

It grows as a densely branching shrub, usually armed with long, sharp thorns. Those thorns make it easy to understand the name “lilythorn,” although the plant is not a true lily.

Its flowers are white, tubular, and shaped somewhat like small trumpets. The narrow tube opens into four spreading lobes, and the flowers may be especially noticeable against the plant’s small green leaves and tangled branches.

After pollination, the plant produces rounded fruits that mature to a very dark purple or black. The species name melanocarpa means “black-fruited.”

Tropical Lilythorn is naturally found only in a very limited part of the Caribbean, including southwestern Puerto Rico and St. Croix. It grows in dry coastal forest and thorny scrub, where it is adapted to intense sunlight, rocky soil, and long periods with little rainfall.

This species is federally listed as endangered, largely because so little of its natural habitat remains. Critical habitat has been designated for it here on St. Croix.

It may appear to be a modest, thorny shrub, but Tropical Lilythorn is one of the Garden’s most important conservation plants—a rare survivor of the native dry forest that once covered much more of our island.