have long decayed away when the tree has reached maturity. Some trees have fibrous aerial roots to gather moisture. At high elevations, and in areas with poor soils or little rainfall, shrub forms are the norm. Flowers are usually bright to medium red but orange-red, salmon, pink, yellow, or orange forms are also found. The flowers appear in clusters on the terminal ends of the branches. Masses of stamens extend from the flower and give the blossoms their characteristic pom-pom shape. The stomata of the leaves are able to close up in the presence of harmful gases, which gives it an advantage over many non-native trees. Uses The reddish brown heartwood of M. polymorpha is very hard, fine textured, and has a specific gravity of 0.7. In native Hawaiian society, it is used in house and heiau construction, as well as to make papa kui ai (poi boards), weapons, tool handles, hohoa (round kapa beaters), and kii (statues and idols). Although the trunk of ōhia is not used to make the kaele (hull) of waa (outrigger canoes), it was used for their nohona waa (seats), pale (gunwales), and pola (decking). Wae (spreaders) were made from the curved stilt roots of ōhia. Pā (fencing) was made from the wood due to its availability; kauila (Colubrina oppositifolia or Alphitonia ponderosa), more durable woods when in contact with soil, was rarer. As the wood burns hot and cleanly, it is excellent wahie (firewood). The lehua (flowers) and liko lehua (leaf buds) are used in making lei. The flowers were used medicinally to treat pain experienced during childbirth. Ōhia lehua is one of the few honey plants that is native to the Hawaiian Islands. Similar species There are about 50 species in the genus Metrosideros in Southeast Asia and the Pacific and as well one species in South Africa. The Hawaiian Islands are home to five species of Metrosideros that are endemic to the islands, meaning they are found nowhere else in the world. These are: Metrosideros polymorpha, M. macropus, M. rugosa, M. tremuloides, and M. waialealae. The species are readily distinguished from one another by the characteristics of their leaves. Metrosideros kermadecensis, from the Kermadec Islands north of New Zealand, has recently become naturalized on Maui and may become a pest species. Several cultivars of M. excelsa, the pohutukawa tree of New Zealand, have been sometimes planted as ornamentals in Hawaii but are