The Native Palms of the Ryukyu Islands of Japan

Japan has six native species of palm tree. Four of these are endemic to Japan. There are a further three species, which have been cultivated in Japan for centuries. These are:
Rhapis excelsa (Thunb.) Henry, J. Arnold Arbor. 11: 153 (1930).
Rhapis humilis Blume, Rumphia 2: 54 (1839).
Trachycarpus fortunei var. wagnerianus Becc., Webbia 5: 70 (1921).

Two native species are found only in the Japanese Ogasawara-shoto or Bonin Islands (typical oceanic islands, located 1,000 km south of Tokyo, Japan). These are:
Clinostigma savoryanum (Rehder & E.H.Wilson) H.E.Moore & Fosberg, Gentes Herb. 8: 465 (1956). Endemic.
Livistona boninensis (Becc.) Nakai, J. Jap. Bot. 11: 222 (1935). Endemic.

The remaining four native species are the subject of this article, and these species are found in the Ryukyu archipelago of Japan or Nansei-shoto. These are:
Arenga ryukyuensis A.J.Hend., Taiwania 51: 298 (2006). Endemic.
Livistona chinensis var. subglobosa (Hassk.) Becc., Webbia 5: 16 (1920).
Nypa fruticans Wurmb, Verh. Batav. Genootsch. Kunsten 1: 349 (1779).
Satakentia liukiuensis (Hatus.) H.E.Moore, Principes 13: 5 (1969). Endemic.

The Ryukyu Islands (Figure 1) are a chain of Japanese islands that stretch south-west from Kyushu to Taiwan: the ÅŒsumi, Tokara, Amami, Okinawa, and Sakishima (Miyako and Yaeyama) islands, with Yonaguni the southernmost. The largest of the islands is Okinawa. These islands have a subtropical climate with mild winters and hot summers.

Ryukyu Islands

Arenga ryukyuensis
This palm is very similar to Arenga engleri from Taiwan, but differs in the pinnae being strongly ribbed adaxially, and the stems are only to about 2 m tall, whereas, Arenga engleri stems grow to over 4 m. tall. Arenga ryukyuensis seeds are also very globose, short and fat, whereas, Arenga engleri seeds are more elongate, also generally larger. Arenga engleri in Taiwan occurs at 200 – 1050 m. elevation, whereas, Arenga ryukyuensis is a lowland species, and occurs from sea-level up to about 300 m. Indeed, the more common localities to see A. ryukyuensis is on the coral limestone coastal rocks, often in the spray zone.

Arenga ryukyuensis and Cycas revoluta growing together in Okinawa, Japan.

Arenga ryukyuensis and Cycas revoluta growing together in Okinawa, Japan. © Phil Markey

A. ryukyuensis is usually seen growning together with Cycas revoluta, which is also very common, and can also be seen throughout the Ryukyu Islands growing on coastal rocks and cliffs.

Both the cycads and the palms are more frequent at lower levels, becoming more scarce at elevation, nevertheless, both are found at the highest elevations in Okinawa.

Right: Cycas revoluta Okinawa, Japan. Left: Arenga ryukyuensis and Cycas revoluta growing together in dense undergrowth, Okinawa, Japan.

Right: Cycas revoluta Okinawa, Japan. Left: Arenga ryukyuensis and Cycas revoluta growing together in dense undergrowth, Okinawa, Japan. © Phil Markey

Arenga ryukyuensis showing form, and white undersides of the leaves.

Arenga ryukyuensis showing form, and white undersides of the leaves. © Phil Markey

Another difference between Arenga ryukyuensis and Arenga engleri is the infructescence. A. ryukyuensis fruits are somewhat exposed and visible from above, growing out of the top of the plant. Whereas, A. engleri fruits are often hidden in amongst the leaves, and almost never visible from above. Fruit of A. engleri ripens from green, through an orange/yellow to dark purplish red. A. ryukyuensis ripens from green through yellow to orange then dark red.

Left: Arenga ryukyuensis fruits. Right Arenga engleri fruits.

Left: Arenga ryukyuensis fruits. Right Arenga engleri fruits. © Phil Markey

Taiwan is a new island that started being pushed up from the sea-bed around 6.5 Ma, by the north eastward movement of the Philippine plate crashing into the Chinese continental margin at 8 cm. per. year. This would have crashed through the Ryukyu archipelago / Luzon volcanic arc, pushing any pre-existing islands into the new Taiwan landmass. It is therefore logical to assume that Arenga existed first in the Ryukyu, which are very much older islands, and was then taken to Taiwan to evolve into Arenga engleri. It is not possible that there has been a land-bridge between Taiwan and the Ryukyu since that time.

Livistona chinensis var. subglobosa
I have written before about this species, so will not spend too much time discussing it here. Only to say that Livistona chinensis does not exist in its truly wild state anymore anywhere within the Ryukyu or Taiwan. In Japan, so-called virgin L. chinensis forest is now found only on the islets of Aoshima and Tsukishima in the Miyazaki prefecture, Kyushu, Japan. The islet of the gods on Aoshima is the extreme northern limit of the species, and this is also officially recognised as the largest single population of the species in Japan consisting of 4000 individuals. But as I have published before, this is not acurate, the largest virgin population of Livistona chinensis var. subglobosa is to be found on a tiny island called Uotsurijima (Japanese) or Diaoyudao (Chinese). This is the largest island of the Senkaku Islands (钓鱼岛及其附属岛屿) or what we know as the Pinnacle Islands. Uotsurijima or Diaoyudao Island located at 25°44’39”N 123°28’26”E has an area of 4.3 square kilometres (1.7 sq mi) and a highest elevation of 383 metres (1,260 ft). L. chinensis is the dominant tree species on this island and I estimate this population to be over 100,000 individuals.

Left: An interesting picture of Livistona chinensis var. subglobosa growing through an old house on Okinawa, Japan. Right: Livistona chinensis var. subglobosa in Taiwan tends to grow much straighter trunks.

Left: An interesting picture of Livistona chinensis var. subglobosa growing through an old house on Okinawa, Japan. Right: Livistona chinensis var. subglobosa in Taiwan tends to grow much straighter trunks. © Phil Markey

It is more often than not that the Japanese Livistona trunks are seen to be leaning, bent, twisted, and show irregular growth patterns. I’ve questioned this in Japan, and was told that the Ryukyu islands experience many typhoons, which bend the trees over. But, coastal Taiwan experiences the same typhoons, and the Taiwan trees tend to have much straighter, upright trunks. Another, difference is that many of the Ryukyu trees produce much more globose, almost round, seeds than do the Taiwan trees. The Taiwan Livistona produce more globose seeds than do the Chinese trees.

Nypa fruticans in habitat on Iriomote Jima, Ryukyu, Japan.

Nypa fruticans in habitat on Iriomote Jima, Ryukyu, Japan. © Phil Markey

Nypa fruticans
Nypa fruticans exists in Japan in one single, very isolated, and inaccessible population at Funaura on the island of Iriomote Jima.
This population of about 28 or more clumps are located a long way up a tidal tributary stream in a large mangrove swamp that surrounds a stunningly beautiful tidal estuary on the north of the island.

Tidal estuary and tidal tributary stream leading through the mangrove swamp. Iriomote Jima, Ryukyu, Japan.

Beautiful tidal estuary and tidal tributary stream leading through the mangrove swamp. Iriomote Jima, Ryukyu, Japan. © Phil Markey

The Nypa population is carfully monitored.

The Nypa population is carfully monitored. Some of the overhanging mangrove has been cleared away to see if this has any effect on the population growth. © Phil Markey

I must say that these Nypa palms are not good examples. Much better examples are to be seen, in much more accessible locations elsewhere in South-east Asia. The Japanese Nypa are located deep in an important mangrove, declared as a natural monument in 1959, well off the beaten track. This mangrove is an important habitat for wildlife, and is best left to the wildlife that inhabit it.

Nypa fruticans reproduces by vegetative propagation, each clump connected together under the mud.

Nypa fruticans reproduces by vegetative propagation, each clump connected together under the mud. © Phil Markey

The population is the world’s northernmost natural occurrence, and it has been rapidly reduced in size. Its genetic diversity examined by the Random Amplified Polymorphic DNA(RAPD) method showed that all 28 individuals examined were genetically identical and had no diversity. They are thus considered clones derived from a single individual by vegetative propagation. Because flowers fail to set fertile seeds, the species is likely to be self-incompatible. The population at Funaura is at an extinction crisis.

Nypa fruticans showing self-incompatible emergent flowers. Iriomote Jima, Ryukyu, Japan.

Nypa fruticans showing self-incompatible emergent flowers. Iriomote Jima, Ryukyu, Japan. © Phil Markey

Satakentia liukiuensis

Satakentia liukiuensis © Phil Markey

Satakentia liukiuensis
Satakentia contains only one species, which is endemic to Japan in the far south of the Ryukyu Islands in the islands of Ishigaki Jima and Iriomote Jima. This genus was named by Harold Moore for Toshihiko Satake, who had noticed it was something special. There is now a museum built to honour Toshihiko Satake within the main population of the palms on Ishigaki Jima.

Trunks can be very tall, brownish/grey, and solitary, topped with a prominent, brown or reddish green crownshaft, which is very distinguishable. With large green pinnate leaves, 3 m. long.
The inflorescences are also distictive, which are branched to two orders, and are borne below the crownshaft.

Trunks have a mass of adventitious roots at the base, and can grow to 20 m.tall. © Phil Markey

Trunks have a mass of adventitious roots at the base, and trunks can grow to 20 m.tall. © Phil Markey

Satakentia liukiuensis is in decline in its natural environment with no known cause, and it was once much more widespread throughout the two islands than it is today. However, plants are being raised in cultivation and are widely planted as a street tree in cities further north, notably Naha on Okinawa.

Satakentia liukiuensis in natural habitat. Ishigaki Jima, Ryukyu, Japan. © Phil Markey

Satakentia liukiuensis in natural habitat. Ishigaki Jima, Ryukyu, Japan. © Phil Markey

Satakentia is grouped in the subtribe Carpoxylinae, which comprises three genus – Carpoxylon, Satakentia, and Neoveitchia. Carpoxylon and Neoveitchia come from Vanuatu and Fiji, it is not clear how the natural distribution could extend to the Japanese Ryukyu for Satakentia.

Satakentia liukiuensis in natural habitat. Ishigaki Jima, Ryukyu, Japan. © Phil Markey

Satakentia liukiuensis in natural habitat. Ishigaki Jima, Ryukyu, Japan. © Phil Markey

Satakentia liukiuensis in natural habitat on Iriomote Jima.

Satakentia liukiuensis in natural habitat on Iriomote Jima. © Phil Markey

There are two main wild populations, the main population on Ishigaki Jima, and a much smaller population on Iriomote Jima with a few individual trees scattered across Iriomote. The Iriomote trees are inaccessible, as they grow in a cemetery, or the isolated trees are remote in the hills.

More info:
Satakentia liukiuensis trebrown.com
Nypa fruticans trebrown.com
Arenga ryukyuensis trebrown.com
Livistona chinensis var. subglobosa trebrown.com

Musa itinerans var. formosana and Musa balbisiana

Musa itinerans var. formosana 1800 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 1800 m elevation
Shitou, Central Taiwan

My latest field trip to Taiwan was funded by the International Palms Society, the New York Botanical Garden, and the Taichung Science Museum to study the distribution of Arenga palms throughout Taiwan and Ryukyu Japan. Luckily the Arenga palms grow in very much the same locations as Musa itinerans var. formosana (Syn. Musa formosana), and so during this extensive trip during June and July I have been able to asses the population of the bananas in Taiwan.

I have, for many years been familiar with Musa itinerans var. formosana growing at high elevation in central and southern Taiwan. I am also familiar with Musa balbisiana growing around Kenting in the far south of Taiwan and also near Chiayi in west central Taiwan. I have seen Musa itinerans var. formosana in the north and east of Taiwan before, but never paid much attention to it. I was also aware that there was once a thriving banana cloth textile industry in the east of Taiwan mainly near Hualien and Ilan, but also all the way down the east coast of Taiwan.

Therefore, at the start of this trip I was expecting to see Musa balbisiana growing all along the east coast of Taiwan as a remnant of the banana cloth industry, as this is the banana used for cloth making in Japan. But there are no Musa balbisiana in the east of Taiwan, and Musa balbisiana was not used for banana cloth manufacture in the east of Taiwan. Musa balbisiana was probably used for textile making in the south of Taiwan and around Chiayi.

At high elevation the red markings on the pseudostem of Musa itinerans var. formosana are less obvious, the fact that highland plants usually hold a skirt of dead leaves may be obscuring it. Very dark red, almost black markings on the pseudostem are quite common sight in the highlands. The male bud is usually dark red. Fruits often seem to have less red colouration, this might be due to residue falling off of the conifer trees onto the more mature fruit turning them black. Nevertheless, high elevation plants do have red blotching on the pseudostem, and they do have reddish/purple coloured fruits, it is just much less obvious.

Musa itinerans var. formosana 1800 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 1800 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 200 m elevation Ilan, East Taiwan

Musa itinerans var. formosana 200 m elevation Ilan, East Taiwan

Musa itinerans var. formosana 700 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 700 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 1700 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana 1700 m elevation Shitou, Central Taiwan

Musa itinerans var. formosana on the east of the mountains, growing at lower (200 – 800 m) elevation usually shows very obvious bright red blotches on the pseudostem. Fruits are much more visible, usually with very bright reddish colour. There tends to be much less red streaking on the male bud than is seen in the highlands.

The most noticeable point is the altitude at which the plants grow. On the west of the central mountains Musa itinerans var. formosana cannot be found growing less than 600 m elevation. However, to the east of the central mountains they start at 200 m elevation. This is probably a result of the eastern side of the mountains being cooler than the west, and receiving more rainfall than the west due to the coastal location. The Arenga palm also grows at lower elevation to the east and north of the mountains.

Musa itinerans var. formosana fruits, Ilan, East Taiwan

Musa itinerans var. formosana fruits, Ilan, East Taiwan

Musa itinerans var. formosana a rare totally yellow bud we found at Shitou, Central Taiwan

Musa itinerans var. formosana a rare totally yellow bud
we found at Shitou, Central Taiwan

So if Musa balbisiana was not the banana used in Hualien and Ilan for the textile industry what banana did they use? There are still a few old women in Hualien who can make banana cloth, it seems the banana they are using is the triploid cultivated banana from cultivation. I wonder if this is because it has been forgotten what banana they used in the past, or if they have moved over to using the cultivated banana because it is better than Musa itinerans var. formosana.

It seems obvious to me that Musa itinerans var. formosana was most probably the original banana used for the Taiwan banana cloth industry, and is the reason it was exported to Lanyu Island. It is probably not the best banana to use, and the fibres are quite weak by comparison to Musa balbisiana, but Musa balbisiana is not found on the east of Taiwan.

Musa itinerans var. formosana cannot be found below 600 m elevation in the far south of Taiwan around Kenting so Musa balbisiana, which does not grow above 300 m elevation is a more suitable banana to grow there.

Musa balbisiana 300 m elevation Kenting, South Taiwan

Musa balbisiana 300 m elevation
Kenting, South Taiwan

Musa balbisiana 300 m elevation Chiayi, central Taiwan

Musa balbisiana 300 m elevation
Chiayi, central Taiwan

Musa balbisiana Kenting showing imbricate male bud

Musa balbisiana Kenting
showing imbricate male bud

Musa balbisiana Kenting After storm damage the male bud becomes much more difficult to identify

Musa balbisiana Kenting
After storm damage the male bud
becomes much more difficult to identify

While I was in Japan I visited the Ryukyu banana cloth region of northern Okinawa. While I was there I questioned the ladies working there about the suitability of different species of banana for use in the banana cloth industry. I was told that Musa balbisiana var. liukiuensis was by far the best banana to use, as it produced the finest thread to make the best quality garments. They said that fabric made from the cultivated triploid banana was very coarse, and makes a heavy sack cloth. Musa textilis was good but not as good as Musa balbisiana var. liukiuensis. But none of the ladies knew about Musa itinerans var. formosana from Taiwan.

Musa balbisiana var. liukiuensis Okinawa Japan

Musa balbisiana var. liukiuensis
Okinawa Japan

Musa balbisiana var. liukiuensis Okinawa Japan

Musa balbisiana var. liukiuensis
Okinawa Japan

Musa balbisiana var. liukiuensis Okinawa Japan

Musa balbisiana var. liukiuensis
Okinawa Japan

Musa balbisiana var. liukiuensis Okinawa Japan

Musa balbisiana var. liukiuensis
Okinawa Japan

More Info:
Musa itinerans var. formosana
Musa balbisiana var. liukiuensis
Musa balbisiana