Throughout our history, humans have used plants for nearly everything from food and medicine to shelter.

Ethnobotany is the field of plant science that focuses on humans’ use of plants and how they are incorporated into our daily lives and activities.

In Hawaii, one popular activity involving plants is fishing. Now, you might assume the plant connection to fishing deals with the cordage required to catch fish.

While Native Hawaiians did use Tourchardia latifolia, known as olona in Hawaiian, to craft fishing lines and nets, they implemented other plants in their fishing efforts. Plant species such as Tephrosia purpurea (auhuhu) and Wikstroemia uva-ursi (akia) were ground and used as fish poisons.

This practice is not unique to the Hawaiian ­Archipelago. In other regions of the Pacific, different taxa are employed to the same effect.

One genus of plants that was traditionally used as a fish poison is Barringtonia. The chemicals present in the bark and fruit of these plants, called saponins, are toxic to fish.

The genus Barringtonia was named in honor of Daines Barrington, who was an English naturalist and lawyer in the late 18th century. He developed a standard format to collect information about the weather, flowering of plants, bird songs and other annual events.

There are about 72 species within the genus. ­Native mostly to the Malesian and Pacific regions, the plants also naturally occur in South Asia, Australasia, East Africa and Madagascar.

There are three centers of diversity — areas where a taxon exhibits greater diversity than it does anywhere else — for this genus: the Malay Peninsula, Borneo and New Guinea. Surprisingly, there is little overlap between the species in New Guinea and those in the ­Malay/Borneo region. This might be due to the fact that the Wallace line — an ancient deep-water boundary between Asia and Australasia — separates these areas.

Barringtonia can range from small to large trees, often with multiple branches. However, some species have a single, thick-stemmed trunk. Plants with this feature are called pachycauls.

All Barringtonia have branches or stems that end in a whorl of foliage. Like many plants, Barringtonia’s flowers will grab your attention before the foliage. Often the flower clusters are born on the branches, but in some species, they are attached directly to the trunk. The flowers contain a profusion of stamen. They might look similar to ohia flowers but do not be fooled, there is no relation. In fact, Barringtonia trees are in the ­Lecythidaceae family, which contains the cannonball tree. This family is known for its unique, showy flowers.

Species like Barringtonia asiatica, also called the fish poison tree, are common in landscaping on Oahu. One exemplary tree can be found on the campus of the University of Hawaii at Manoa outside of the chemistry building. Rarer species, including the B. papuana, can be viewed now in flower at the Harold L. Lyon Arboretum.

Under no circumstances should material be removed from any Barringtonia tree, and please observe all state fishing regulations.

Jesse Adams is a botanist at the Harold L. Lyon Arboretum, where he works to catalogue, propagate and conserve the plant diversity found there.