• Biodiversity Ohia lehua
  • Ohia lehua

    Metrosideros polymorpha

    A Honeycreeper’s Mainstay—the red flowered Ohia

    After the onslaught of invasive species introduced to Hawaii, there are relatively few native species that have been able to compete. The showy, red-flowered ohia is one of the hardiest competitors the Hawaiian Islands have produced. They are the most common tree species in Hawaiian forests and form a mainstay for hawaiian honeycreepers. The bright red blossoms on these trees are actually the long filaments of the flowers.

    Distribution

    There are 5 species of Ohia endemic to the Hawaiian islands; Metrosideros polymorpha is the most common of all the species. It is found on all the main islands in a wide range of habitats. It is an early colonizer of lava flows and can be found from the coast up to about 8,500 feet. The name polymorpha (“many forms”) alludes to the diverse nature of this plant. It can grow as a stunted bush in bogs, on windswept hillsides, on lava flows, and as a giant tree in lush rainforest habitats. But its not only the size of the tree that changes, the leaves of this plant have different growth morphologies depending on where it lives.

    General Description of Ohia

    Ohia grows as a small bush to a large tree in Hawaiian forests. The bark of the tree is light gray, rough, fissured, and scaly. In moister areas the bark may be difficult to see because it is often covered in moss, lichens, ferns or other Hawaiian epiphytes. The leaves are alternate and arranged in a ninety degrees to one another. While size and texture vary, they are generally from a half inch to two inches long. It is common to see small bumps on the leaves of Ohia. These galls are caused by small insects called psyllids that lay their eggs in the leaf tissue. As they grow, a compound is secreted which simulates plant growth homorne, stimulating the plant to grow abnormally around the insect.

    The flower blossoms of Ohia are formed by clusters of tiny flowers. The petals are relatively small and insignificant. The part that most people see when looking at the blossum from a distance are lots of stamen. The long filaments of this male reproductive part are red and look somewhat like hair. Lehua means “hair” and thus Ohia lehua refers to these hair-like blossoms.

    Ohia and Legends

    These bright blossuos were particularly attractive to Hawaiians. They believed that picking an ohia lehua blossum brought rain with it so it was best not to pick one on the way into a forest. They picked the blossoms on the way out!

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    Written by Rob Nelson

    Rob is an ecologist from the University of Hawaii. He is also an award-winning filmmaker. As principle director of Untamed Science productions his goal is to create videos and content that are both entertaining and educational. When he's not making science content, he races slalom kayaks and skydives.

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