Metroxylon amicarum

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Metroxylon (meht-ROKS-ih-lohn)
amicarum (ahm-ee-KAR-oom)
Hawaii. "Flowers arising from lowest leaf bases, not on tippy top, as in other species in the genus". Photo by Geoff Stein.
Scientific Classification
Genus: Metroxylon (meht-ROKS-ih-lohn)
amicarum (ahm-ee-KAR-oom)
None set.
Native Continent
Habit: Solitary
Leaf type: Pinnate
Survivability index
Common names
English name: Caroline Ivory Nut Palm, Pohnpeian name: Oahs (Ohs), Chuukese name: Foun Rúpwúng, Rúpwúng. Rúpwúng [Foun Rüpwung from Web] (Chuuk), Oahs (Pohnpei)

Habitat and Distribution

Endemic to the Caroline Is., Marianas. Usually found in wet, swampy areas and river sides.
Keanae Arboretum, Maui. Photo by Forest & Kim Starr.
Found only on the Islands of Pohnpei and Chuuk. This palm was probably introduced to some areas of Micronesia, [including Chuuk,] either in the prehistoric period, or shortly after European contact began.


Growing to heights of 25 m (80 ft) or more. Leaf shape and morphology: Leaves are large (25-30 ft) in length. Divided once; leaflets are linear and parallel veined (3-4 ft. long), even pinnately compound. Leaflets pointing posterior arranged dorsally, unlike coconut palm that has its leaves arranged laterally. Entire but sharp leave margins. Stem type: Woody (lignified) stem often grows to heights 80 feet (25 m) or more. Prickly, large stem 3-5 ft. in diameter. Young ones are pubescent. Floral characteristics: Flowers on large inflorescence branches located axillary. Flowers are produced regularly which enables it to constantly bear fruits. Fruit: Round (4-6 in., 10-15 cm) in diameter. Fruit skin (exocarp) is scalelike. Fibrous mesocarp; white meat (endosperm) covering embryo. Embryo is soft when young and hardens when old. Unlike other botanically related palms in the genus Metroxylon, this palm tree flowers regularly for a number of years rather than flowering once and dying. It has large 10-15 cm (4-6 in) wide, round, scaly nuts. ( Editing by edric.

This plant is a large palm tree that grows to heights of 25 m (80 ft) or more. Unlike other botanically related palms in the genus Metroxylon, this palm tree flowers regularly for a number of years rather than flowering once and dying. Its large 10-15 cm (4-6 in) wide, round, scaly nuts are eaten by pigs. Because the "meat" (endosperm) of the nut is white and hard, this plant is known in English as the "ivory nut palm." (

Usually growing to 20, but occasionally over 25 m, these massive palms have solitary trunks with widely spaced leaf-scar rings and old leaf bases attached to the top. Leaves are pinnately arranged, 5 m long, on one meter petioles. The lanceolate leaflets are dark green to 1 m and occur on the rachis at varying angles, creating a plumose leaf. Unlike its monocarpic relatives, this species has a narrow inflorescence which develops within the leaf-bases; the stem is erect until the fruit matures and then sags to a pendent cluster. The single-seeded fruit are 9 cm long, extremely hard, and are covered in brown, glossy scales. Of all species in the genus it is probably the most hardy to cold. It is found only in Micronesia. It is threatened by habitat loss.


Growing Comments: "All Metroxylon palms are large & impressive & all except M. amicarum will die after they produce flowers & fruit. They actually prefer swampy conditions, but still are excellent growers in our garden, where drainage is excellent. These are all relatively fast growers & two of our largest M. amicarum have grown from about one foot overall height to about 25 ft overall height in seven years, but no trunk yet. Growth rate is about a 6.0-7.0 on a scale of 1-10." (BGL)

Comments and Curiosities

Etymology: The specific epithet is from the Latin - amicarium literally; "of friends."

External Links


Phonetic spelling of Latin names by edric.

Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.

Special thanks to, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.

Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).

Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.

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