Pelagodoxa henryana
Pelagodoxa (pehl-ah-go-DOKS-ah) henryana (hen-ree-AHN-ah) | |||||||
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North Queensland, Australia. Photo by Karl Gercens III. | |||||||
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Contents
Habitat and Distribution
Marquesas, Solomon Is., and Vanuatu. There are no known wild populations; there are three documented anthropogenic sites in Vanuatu, Marquesas and Fiji Islands.It is considered to be native to the Marquesas, an isolated group of islands some 8° south of the Equator in the central Pacific Ocean, where it occurs naturally in very moist, humid valleys as an understorey component. This population is only small and obviously endangered as regeneration has been restricted due to the encroachment of agriculture in the vicinity. Naturalisation of Pelagodoxa henryana has occured in the Solomon Islands, where a cultivated grove near a long abandoned settlement has regenerated. (Palms & Cycads)
Description
Pelagodoxa henryana belongs to the monotypic genus Pelagodoxa (Pelagodoxeae: Arecaceae). It is an unarmed, solitary palm to 11 m height. The stem is up to 15 cm in diam, and the leaf scars are closely spaced. The leaves are large, undivided, pinnately ribbed with a bifid apex, and may extend to 3 m long and to about 1 m wide. The upper surface is green and glabrous, and the lower surface has a distinctive silvery glaucous bloom. The petiole is stout and short, to about 22 cm long. The leaf bases are densely tomentose, do not form a crownshaft but have a loose entanglement of fine fibres along the lower margins. It is monoecious, and the inflorescences are interfoliar, not extending beyond the leaves and paniculately branched. The fruit is globose, with a corky warty epicarp that is tan colored at maturity. Three size cohorts occur that differ mostly in proportion (the two smaller ones ripen with a pulpy, orange, fragrant mesocarp, the largest ripens to a tan fibrous mesocarp): 2.0 cm in diam. (Vanuatu); 5.5 to 6.0 cm in diam. (Fiji); 10 to 15 cm in diam. (virtualherbarium.org) Editing by edric.
Notes: The native names in the Marquesas are enu and vahane. Known only from a single, probably anthropogenic population at Taipivai on Nuku Hiva. On the main islands it is occasionally cultivated near churches and in yards. Butaud (2009) suggested it may represent a Polynesian introduction. Recently prehuman pollen of a palm belonging to Iguanureae (same tribe as Pelagodoxa) was found on several of the Austral islands. P. henryana is tentatively considered indigenous in the Marquesas but extinct in the wild. (Dr. David Lorence)
Detailed Scientific Description |
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Unarmed, solitary palms to 11 m high, the stem to 15 cm in diam, smooth, with leaf scars closely spaced. Leaves large, the leaf bases densely tomentose, not forming a crownshaft but with a loose entanglement of fine fibers along the lower margins; petioles short and stout, 22-70 cm long; blades elliptic, about 3-3.5 m long, 0.9-1 m wide, at first undivided but soon shredded into irregular pinnate divisions by the wind, pinnately ribbed, the base cuneate to obtuse, the apex bifid, the margins coarsely dentate distally, the upper surface green and glabrous, the lower surface with minute scale-like lepidia and having a distinctive silvery glaucous bloom. Inflorescences interfoliar, not extending beyond the leaves, monoecious, spathe boat-shaped, shorter than paniculately branched inflorescence to about 50 x 30 cm, pubescent, the basal branches 3-4-partite, the upper ones simple, each subtended by a bract the lowest about 16 cm. long and spathe-like, the upper bracts progressively smaller to less than 1 cm long; flower-bearing branches about 20 cm long, about 5 mm in diam.; flowers sessile, grouped in threes except near the apex, partly sunk in the spirally arranged cavities of the branch, each group with 2 staminate flowers with a single pistillate flower between them, the staminate flowers blooming first; apical cavities each containing a single staminate flower; the subapical cavities each contain 3 flowers, but the carpellate flower is commonly vestigial. Staminate flowers with 3 imbricate, convex, suborbicular, sepals about 2 mm long; petals 3, 2 mm long, valvate; stamens 6, the ovulary vestigial. Pistillate flowers bibracteate, the striate bracts 2 mm. long, enclosing the unopened flower; sepals 3, 2 mm. long, imbricate; petals 3, valvate, 2 mm. long; staminodes very small; ovulary subglobose, becoming unilocular and 1-seeded in fruit. Fruits 12 or more per inflorescence, globose, 10-15 cm in diam., with a corky, warty surface, tan colored at maturity, ripening to a soft, fibrous mesocarp, endocarp hard, smooth, enclosing a single seed. Seed globose, obscurely polyhedral, covered with a thin pale brownish testa, the embryo basal; endosperm about 2 cm. thick, hard, white; with central cavity. (Dr. David Lorence) |
Culture
Pelagodoxa henryana is an exytremely beautiful, somewhat difficult palm to grow but well worth the effort. It is absolutely gorgeous and not overwhelmingly big. It is adapt to the humid tropical climates, but is usually not cultivated. It elegant foliage and small stature make it suitable for a smaller landscape. People who live in colder climates can still enjoy the palms as potted plants. Seed is not often available from cultivated plants. For this reason, it has been an expensive item, normally reserved for collectors. Even in a greenhouse it can be a bit of challenge.
Growth rate: Usually grows relatively fast in favourable tropical climates, with the formation of a trunk commencing after about 6 years.
Soil requirements: It has a fibrous root system and benefits from deep organic, soils that are fertile as long as they are well drained.
Watering: It prefers adequate moisture to look its best. Don't let sit in water. Indoor, potted palms should not be over-watered.
Light: Likes a half-shaded, sheltered position. If home-grown, give some sun as with most tropical palms.
Fertilization: Need a perfect fertilizer diet including all micro nutrients and trace elements three times a year if not grown in rich soil.
Aerosol salt tolerance: It is moderately tolerant, but does a lot better inland then it does on the coast. Hardiness: This palm is tender and is suited for tropical or subtropical climates, and not like cold. Seedling growth arrests below 15° C.
Wind hardiness: It is not tolerant as the fronds tatter easily and requires wind-sheltered spots.
Propagation: The fresh seeds take 4-6 months to germinate. If not properly treated, the seed does not have long shelf life. Shade and abundant moisture for seedlings and juveniles is essential in a very well protected area if the leaves are to retain their fullness, as they are easily split and spoiled by wind and even mild exposure. (llifle.com)
Comments and Curiosities
This is a monotypic genus.
The circuitous route of discovery and documentation of Pelagodoxa and the meandering process of investigating its phylogenetic position are as unique as its morphology and anatomy suggests. Beccari’s assessment of Pelagodoxa being a ‘grande nouveauté’ is still valid, as it remains one of the greatest novelties in the palm family, both morphologically and historically. (J.L. Dowe. 2006)
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Natural History: Pelagodoxa henryana is found in cultivation or anthropogenic habitats with a peculiar distribution pattern attributed to human dispersal. The fruits have poor dispersal by floatation in water. Populations have been documented from the Marquesas Islands and Melanesian Islands of the Southwest Pacific, including San Cristobal and Mikiri Harbour, in the Solomon Islands. The type species, P. henryana was found in Nuku Hiva, Marquesas Islands. The smallest fruited Pelagodoxa was vouchered in 1983 and observed and documented in Vanua Lava, Vanuatu, with reports of an inland population on at least one island. Pelagodoxa henryana has naturalized in many of these regions. It is also found in cultivation throughout many private and public botanical gardens. Seeds of the Marquesas and Fiji source palms have been documented to produce viable seed. The anthropogenic sites may suggest a food source or famine food, as the fruit endosperm is edible. (virtualherbarium.org) Threats to Survival: Pelagodoxa henryana is already extinct in the wild. Being monotypic, Pelagodoxa represents a significantly greater loss of biodiversity than a genus with numerous species. The Southwest Pacific islands have been identified as having the highest proportions of the most highly threatened palms in the world. Although P. henryana has been observed reproducing in the wild, the small number of individuals that are known do not represent a healthy, viable population structure. The known populations are subject to habitat destruction, and in cultivation the palm seedlings are highly susceptible to fungal attacks and disease. While seed banking protocols have recently been applied to palms, the large seed size does not make this palm a good candidate for seed storage. (virtualherbarium.org) Conservation: Pelagodoxa henryana has attracted a great deal of interest historically and currently resulting in research, ex situ collections, and private collections. Documented ex situ collections of the Fiji and Marquesan source palms are managed within botanical gardens internationally. Recommended management strategies include: protection of habitat areas in the Marquesas and Vanuatu populations; invasive species management and long-rang monitoring; establish new wild populations; establish effective genetically diverse ex situ populations; collaborate to accomplish conservation biology research; adhere to invasive weed, pest management, and quarantine procedures; conduct molecular studies that include all known individuals and populations in the Marquesas, Fiji and Vanuatu. Repatriation (out-planting) from cultivated sources should be considered. (virtualherbarium.org) Pelagodoxa henryana is a critically endangered palm known in the wild from only a single population in a valley on Nuku Hiva, one of the Marquesas Islands in French Polynesia. Because much of the island has been cleared to make room for coconut plantations, native trees like this have been pushed back into remnant populations on slopes. There are only 12 full-grown individuals of this palm species left in this presumably wild population at c. 135 m elevation. The species relies heavily on cultivation to survive. (NTBG) IUCN Red List - Critically Endangered: 1998. Edible Fruit: At maturity, the mesocarp is of a pasty, lightly fibrous texture, similar to avocado pulp, with a sweet pungent odour which some may find offensive, somewhat resembling a combination of mild durian and custard apple flavours. The seed is enclosed in a smooth endocarp which becomes brittle and cracks prior to germination. A recent report of a Pelagodoxa sp. which has fruits to only 2cms in diameter at maturity as occuring in Vanuatu, has fueled speculation that there may be another species, but a determination has yet to be completed. One may presume at this stage that this small population in the Banks Group may be depauperate specimens of Pelagodoxa henryana . Further study is presently being carried out. The cultivation of Pelagodoxa appears to present no problems within the humid tropics. Shade and abundant moisture for seedlings and juveniles is essential in a very well protected area if the leaves are to retain their fullness, as they are easily split and spoiled by wind and even mild exposure. Growth can be fast, with the formation of a trunk commencing after about 6 years. (Palms & Cycads) Garden uses: This palm has only recently been introduced to cultivation, but is becoming very popular in the tropics and sub-tropics as a garden and container plant. It is an excellent landscaping palm when set among taller trees as a specimen but is even better when multiple plants are grown together. It is specially for small gardens where other palms will grow out of scale. Plant this palms in containers and feature it in a prominent spot on the patio. Other uses: The anthropogenic sites may suggest a food source or famine food, as the fruit endosperm is edible. At maturity, the mesocarp is of a pasty, lightly fibrous texture, similar to avocado pulp, with a sweet pungent odour which some may find offensive, somewhat resembling a combination of mild durian and custard apple flavours. (llifle.com) "Another beauty far too tropical for my area of the world. This is one of the most sought after palms for growers in the tropics. It develops magnificent large, barely split leaves with a striking white underside. Even in a greenhouse it can be a bit of challenge here in So Cal. A native of the Marqueses island, this palm is basically extinct in the wild (maybe 10-12 left). It has one of the most ornamental and unusual seeds of all palms- looks sort of like a large rubber chew toy for a dog with knobs all over it. The 'original' variety from the Marqueses have large baseball-sized seed, while variants of this on other islands in the South Pacific (notably the Vanuatu Islands) have seed almost 1/4 this size- just golf-ball sized, and have more orange in the leaves..)" (Geoff Stein) This strange and very beautiful palm from the tropical Marquesas Islands in the South Pacific sports a moderately tall, slender, smooth trunk topped by a spreading crown of large, undivided leaves that are whitish below and may be split by strong winds. The much sought after seeds are very large and round and germinate within a few months. In its native habitat, Pelagodoxa is critically endangered and the species relies heavily on cultivation to survive. (RPS.com) Pelagodoxa henryana (Fiji Type): Sports a moderately tall, slender, smooth trunk topped by a spreading crown of large, undivided leaves that are whitish below and may be split by strong winds. The much sought after seeds are large, round and germinate within a few weeks or months. Pelagodoxa is critically endangered and the species relies heavily on cultivation to survive. In fact, no true wild habitat is known and the palms origins remain somewhat unclear. The type from Fiji in the South Pacific has large fruits, around 6 cm in diameter. (RPS.com) Pelagodoxa henryana Becc. is a rare palm from Nuku Hiva in the Marquesas Islands reportedly growing in dense rain forest about 135 in above sea level in a humid valley. This description from Genera Palmarum probably gives some indication of the rarity of the palm. Its status on the island is doubtful in that one search party was unable to locate the palm, but another report speaks of collecting fruit. Just how and when this palm reached Fiji I do not know. John Parham (Plants of the Fiji Islands 1972) reports that three specimens had been growing in the Suva Botanical Gardens (now the Thurston Gardens) but that they had died. The photograph in Genera Palmarum (p. 142) was certainly taken in the Thurston Gardens, but although I have lived in Fiji for many years, I do not remember having seen the palm. My real interest in palms began in about 1976 -- I attended my first International Palm Society Biennial in 1978 -- and I assumed that Pelagodoxa henryana had been lost to Fiji. However, I kept looking in all the old gardens in Suva and encouraged several friends to do the same. My best collector was Nacani, who seemed to have inumerable relatives who died with monotonous regularity; as a result, he was always short of money. He came to my house one day with an almost round, smooth seed, slightly smaller than a golf ball and announced that it was the seed of a palm. I had never seen a palm seed that looked like that so I demanded an explanation. The more details Nacani gave me, the more excited I became, particularly when he mentioned the corky warts on the fruit. He led me to an abandoned garden quite close to the Thurston Gardens and there, in all its glory, was the palm. It took only a quick look for me to know that it was P. henryana. Better still was the fact that it was loaded with several hundred seeds in various stages of development and, on the ground below, there were about 40 seedlings growing strongly. Fortunately, I knew the owner of the property so we stole all the seedlings and then phoned and told the owner what we had done. As I expected, he approved. The seedlings grew well, as did many more plants, which I have grown from seeds from this palm. Over the years I have sold and given away more than 100 palms to friends who had fairly permanent gardens. Four specimens have been planted in the Botanical Gardens section of the University of the South Pacific in Suva and three in the Thurston Gardens. All of these are growing well. Collectors coming to Fiji have also been happy to take a few seeds with them, and it soon became known, through the Palm Society, that there was a fruiting P. henryana in Fiji. This led to numerous letters asking for seed. The request I do remember was from Germany -- a Society member rang me to see whether seed was available. Unfortunately he forgot that there was a 12-hour time difference between Germany and Fiji. At 3 a.m. I was not very receptive to a request for seed! A member in southwestern England wrote asking for seed. As I had a friend flying to the U.K., it was arranged that he would carry two seedlings. The member rode a bus from his home to Heathrow, picked up the seedlings, and rode the bus back to his home. The seedlings were out of the ground for not much more than 60 hours and were not troubled by the trip half way around the world. (R. H. (DICK) PHILLIPS)
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External Links
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- http://www.palms.org/principes/1996/pelagodoxa.htm
- http://freakofnaturezzz.blogspot.com/2009/06/pelagodoxa-henryana.html
- By Dr. David Lorence.
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, 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.