Wiliwili facts for kids
Quick facts for kids WiliwiliErythrina sandwicensis |
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| Raceme of wiliwili | |
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Erythrina
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E. sandwicensis
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| Erythrina sandwicensis O.Deg.
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The Wiliwili (Erythrina sandwicensis) is a special type of flowering tree that belongs to the pea family, called Fabaceae. It is found only in the Hawaiian Islands. It's the only kind of Erythrina tree that naturally grows there. You can usually find Wiliwili trees in dry forests on the leeward (drier) sides of the islands, up to about 600 meters (2,000 feet) high.
The name Wiliwili means "repeatedly twisted" in the Hawaiian language. This name comes from its seedpods, which twist open to show the seeds inside.
Contents
About the Wiliwili Tree
Appearance and Growth
Wiliwili trees can grow to be about 4.5 to 9 meters (15 to 30 feet) tall. They have a thick, twisted trunk that can be 0.3 to 0.9 meters (1 to 3 feet) wide. The bark is smooth with small cracks and has gray or black spines up to 1 centimeter (0.4 inches) long. On older trees, the main trunk's bark often looks orange because of a type of alga growing on it.
Leaves and Flowers
The Wiliwili tree loses its leaves during the summer, which is the dry season in Hawaii. This usually happens from late April or May. In the wild, trees typically lose all their leaves before their flowers appear. However, trees that are grown by people might keep some leaves during flowering time.
The flowers bloom from April to July, during the first part of the dry season. They grow on branches that stick out almost horizontally and are 7.5 to 15 centimeters (3 to 6 inches) long. The flowers can be many colors, like orange, yellow, salmon, greenish, or whitish. Sometimes, you can see all these colors in one group of trees!
Pollination and Seeds
Like other Erythrina trees, the Wiliwili is pollinated by birds. The way its flowers grow on horizontal branches and have an upright petal helps small passerine birds pollinate them. Other Erythrina trees are often pollinated by hummingbirds, but hummingbirds don't live in Hawaii.
After flowering, seedpods grow and stay on the tree. The seeds remain attached even after the pods open. Heavy rains, usually starting around November, wash the seeds off the tree. Many seeds sprout quickly. A young Wiliwili plant can grow up to 1.2 meters (4 feet) tall before the next dry season begins.
Why Does it Have Spines?
It's a bit unusual for the Wiliwili tree to have spines. Many plants in the isolated Hawaiian Islands have lost their spines over time because there were no large animals like deer or cows to eat them. Scientists think the Wiliwili is closely related to other spiny trees, like E. tahitensis from Tahiti and E. velutina from South America and the Caribbean.
Where Wiliwili Grows
You can sometimes see Wiliwili trees growing in gardens or parks in Hawaii. They are easy to grow from cuttings. There used to be seven other types of Erythrina trees grown in Hawaii, but most of them have been destroyed by a tiny insect called the gall wasp (read more about this in the Conservation section). These other Erythrina trees were popular for planting along streets in dry areas and as windbreaks around fields.
You can tell a Wiliwili tree apart from other Erythrina trees that were brought to Hawaii. Wiliwili pods usually have only one to three red or yellow-orange seeds, and these seeds sink in water. The other Erythrina trees have more brown seeds, and their seeds float in water.
How Hawaiians Used Wiliwili
Native Hawaiians used Wiliwili wood for many things because it is very light. They made mouo (fishing net floats) and ama (floats for outrigger canoes). They also made very long surfboards called olo, which were about 5.5 meters (18 feet) long. Only Hawaiian royalty were allowed to ride olo surfboards.
Sometimes, the light wood was used for the main body (waʻa) of outrigger canoes. These canoes were meant for fun or training near the shore. The shiny orange-red seeds were often strung together to make beautiful lei (flower necklaces).
Protecting the Wiliwili Tree
Like other native Hawaiian plants, the Wiliwili tree faces threats from non-native plants and animals. These introduced species often don't have the same natural enemies (like diseases or insects) in Hawaii that they have in their home countries, so they can grow very quickly and outcompete native plants.
In December 2005, it was reported that the Wiliwili trees in Hawaii were in danger from a tiny insect called the gall wasp, Quadrastichus erythrinae. This wasp was first seen in Hawaii in April 2005. It seems to have traveled very quickly from places like Taiwan, Singapore, and China in just two years. This wasp was so new that scientists only formally named it in 2004! It's thought to have come from Africa, but how it spread so fast across Asia, the Pacific Ocean, and North America is still a mystery.
Most of the Erythrina trees that were brought to Hawaii have died because of this gall wasp. Native Wiliwili forests have also been badly affected, especially a place called Puʻu o Kali on the island of Maui. This area used to be one of the best examples of a dryland forest in Hawaii. Scientists are now studying how two invasive insects (the African bruchid beetle and the erythrina gall wasp) are harming the Wiliwili tree.
To help fight the gall wasp, the Hawaii Department of Agriculture released another type of wasp, Eurytoma erythrinae, in December 2008. This second wasp is a biocontrol agent. Eurytoma wasps lay their eggs inside the galls (small bumps) created by the Quadrastichus wasps. The Eurytoma larvae hatch faster and eat the Quadrastichus larvae, helping to control the damaging gall wasp population.
History of the Wiliwili Name
The group of trees called Erythrina was first named by Carl Linnaeus in 1753. The name "Erythrina" means "red," referring to the color of flowers on some of these trees.
Over time, the Hawaiian Wiliwili tree was given different scientific names. In 1830, Charles Gaudichaud-Beaupré named it Erythrina monosperma. This name was used by many scientists who studied Hawaiian plants throughout the 1800s.
Then, in 1932, a scientist named Otto Degener changed the name to Erythrina sandwicensis. He didn't say why he changed it, but this is the name that has been used ever since.
Wiliwili Hula Chant
There is an old Hawaiian hula chant that mentions the Wiliwili tree. This chant tells a story about a shark and the sea.
- Auwe! Pau au i ka manō nui, e!
- Lala-kea niho pa-kolu.
- Pau ka papa-ku o Lono.
- O ka ai ia e ka manō nui,
- O Niuhi maka ahi,
- Olapa i ke kai lipo.
- Ahu e! au-we!
- A pua ka wiliwili,
- A nanahu ka manō
- Auwe! pau ai i ka mano nui!
- Kai uli, kai ele,
- Kai popolohua o Kane.
- A lealea au i kaʻu hula,
- Pau au i ka manō nui!
- Alas! I am seized by the shark, great shark!
- Lala-kea with triple-banked teeth.
- The stratum of Lono is gone,
- Torn up by the monster shark,
- Niuhi with fiery eyes,
- That flamed in the deep blue sea.
- Alas! and alas!
- When the flowers of the wiliwili tree,
- That is the time when the shark-god bites.
- Alas! I am seized by the huge shark!
- O blue sea, O dark sea,
- Foam-mottled sea of Kane!
- What pleasure I took in my dancing!
- Alas! now consumed by the monster shark!
See also
In Spanish: Erythrina sandwicensis para niños
