Caryota+mitis

== toc Figure 1. //Caryota mitis// (Clustering Fishtail Palm)

= = = = = = = = =Introduction = Southeast Asia is a hotspot for palm diversity - this area alone contains almost half of all the palm species identified in the world. In Singapore, there were a total of 54 recorded species of palms, but only 42 species are extant today. The most distinctive of the palms would be //Caryota mitis// (figure 1) – a fairly common palm in Singapore easily recognized by its “fishtail-like leaflets”. There are a total of 13 species in the //Caryota// genus, but only one species – //Caryota mitis// – is found in Singapore.

 The //Caryota// genus is unique because they are the only palms with bipinnate (branches twice from the main stem) leaves (figure 2, right, above) and are therefore easily recognized. In addition, all //Caryota// species, including //C. mitis//, are monocarpic (syn: semelparous, hapaxanthic). This means they only flower (and set fruit) once in their lifetime before it dies. Fortunately, as the common name of C. mitis suggests, the “Clustering Fishtail Palm” frequently grow in clusters of stems rather than solitary stems and only the flowering stem dies after fruiting (figure 3, left, below). For this reason, //C. mitis// is often planted as an ornamental palm in Singapore, and around the world. Locally, our National Parks Board (NParks) do plant some species of //Caryota// as an ornamental plant around Singapore, such as //C. mitis// and //C. no//.

 Despite //C. mitis// being common (more than 1000 individuals) in Singapore, little is known about the biology and ecology of //C. mitis//. In fact, it is common not only on mainland Singapore, but also on Pulau Ubin, where a simple survey along trails found 2657 individuals. That is a staggering number of individuals given the small size of Pulau Ubin! Today, there is ongoing research over at the National University of Singapore (NUS) to find out more about this common but little known palm.

 Figures 3 Clustering growth form of // C ////. mitis // ; hollows indicate dead, mature stems =Species description (Field identification) =  Extremely common in Singapore, especially around disturbed areas and along roads; abundant on Pulau Ubin, Kent Ridge Park, and secondary forests in Singapore. Often cultivated and seen in residential areas. Widespread over the whole of Singapore, including areas such as East Coast Park, Changi, Pearl Hill Terrace and Bukit Timah Nature Reserve, among other areas.

 Easily identified by the bipinnate leaves with fishtail-like leaflets (limited to //Caryota// genus and //C. mitis// is the only native //Caryota// to Singapore). While the fishtail-like leaflets is distinctive, it may be confused with palms such as those from the //Korthalsia// genus(tribe: Calameae) (e.g. //K. rigida// and //K. rostrata//) which may also have fishtail-like leaflets. However, as the species epithet suggests, //C. mitis// is an unarmed palm (figure 4) (as all //Caryota// are) and does not have spines on its stem, unlike the rattans in the //Korthalsia// genus. In addition, the leaves of //Caryota// are bipinnate, while the leaves in all other palms are not.

 Medium-sized, clustering palm that grows to a maximum of 8m (generally less than 5m in Singapore ). Inflorescence branched with many rachilla, flowers cream to purple in colour. Fruits round, about 1 cm across. Green when unripe, turns orange, red or even purple when ripe.

 For those who are interested in a more complete and detailed description with accompanying pictures, refer to full species description at the end of the page!

Figure 4. Unarmed stem of //C. mitis//. = = = Nomenclature =

Etymology
//Caryota// //mitis// was first described in 1790 by Loureiro in Vietnam. The genus ‘//Caryota//’ is derived from ‘caryon’, which means a nut in Greek in reference to their fruits. The species epithet ‘//mitis//’ means unarmed in Latin, referring to the lack of spines in //C. mitis// (figure 4). Incidentally, all species within the //Caryota// are unarmed. Refer to [|this link] for more information by NParks about //C. mitis//!

Synonyms
 //Caryota furfuracea// Blume ex Mart (1838), //Caryota// //griffithii// Becc. (1871), //Caryota// //javanica// Zipp. ex Miq. (1856), //Caryota// //nana// Linden (1881), //Caryota// //propinqua// Blume ex Mart. (1838), //Caryota// //sobolifera// Wall. ex Mart. (1838), //Caryota// //sobolifera// Wall. (1848), //Caryota// //speciosa// Linden (1881), //Drymophloeus// //zippellii// Hassk. (1842) ,//Thuessinkia// //speciosa// Korth. (1855).

Common names
<span style="font-family: Arial,Helvetica,sans-serif;"> Fishtail palm, clustering fishtail palm, rabok, tukas.

=<span style="font-family: Arial,Helvetica,sans-serif;">Distribution = Figure 5. Distribution of //C. mitis//. <span style="font-family: Arial,Helvetica,sans-serif;">(Image take from [|Hahn and Sytsma, 1999 - Molecular systematics and biogeography of the Southeast Asian genus Caryota (Palmae) in Systematic Botany 24(4): 558-580]). <span style="font-family: Arial,Helvetica,sans-serif;"> While the //Caryota// genus spans from India to Northern Australia, the native distribution of //C. mitis// (figure 5) is limited to the rainforests of Indo-China and Southeast Asia - from the Andaman and Nicobar Islands, to Myanmar, Southeast China, to Southeast Asia and Sulawesi. However, //C. mitis// has been noted to have been naturalized in Southern Florida, Hawaii and the northern regions of Australia (e.g. Darwin, possibly northern Queensland).

=Flowers and fruits=

Male Flowers
<span style="font-family: Arial,Helvetica,sans-serif;"> The inflorescences in the Caryota genus are bisexual, with separate male and female flowers. The flowers come in triads (one female flower between two male flowers), and are protandrous (meaning the male flowers mature before the female flowers (figure 6) – normally a technique to minimise self-fertilisation).

<span style="font-family: Arial,Helvetica,sans-serif;"> Figure 6. Triad of flowers in //C. mitis//. Distinct development of male flowers (labelled M) before female flowers (labelled F). <span style="font-family: Arial,Helvetica,sans-serif;"> The male flowers are morphologically distinct from female flowers, and are easily recognized. They come in various colours, ranging from cream to dark purple (figure 7). The male flowers are elongated with 3 petals and numerous stamens, and seem to produce copious amounts of pollen. One individual produced so much pollen it appeared that the entire inflorescence was “bathed” in pollen (figure 8). It appears that there is a pattern when it comes to anthesis - only some male flowers will open on the first day (figure 9 - day 1). On the second day, the rest of the flowers will open, while the ones that were previously open the day before would have fallen off (figure 9 - day 2). On the third day, all the flowers would have died and most have fallen off (figure 9 - day 3). This cycle is illustrated in figure 9. The male flowers only last for a day.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%; line-height: 1.5;"> <span style="font-family: Arial,Helvetica,sans-serif; line-height: 1.5;"> Figures 7 (left) & 8 (right). Variation in flower colour in //C. mitis// - cream to dark purple (left). Copious amount of pollen produced by //C. mitis// individual (right).

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%; line-height: 1.5;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 9. Flowering of male flowers in //C. mitis// on a temporal scale.

Female flowers
<span style="font-family: Arial,Helvetica,sans-serif;"> The female flowers are much less fancy (figure 10). They are globular in shape, with a trilobed stigma and like the male flowers, have 3 petals too. However, do not look as fanciful as the male flowers and no insects have yet been observed to visit the female flowers. Their pollination mechanism is still unknown.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%; line-height: 1.5;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 10. Female flowers of //C. mitis// - globular shape is clearly distinct from the elongated shape of the male flowers.

Fruits
<span style="font-family: Arial,Helvetica,sans-serif;"> The fruits of //C. mitis// are about 1-2 cm in diameter, red to dark purple when ripe and usually has one seed (figure 11). The fruits are eaten by many animals (refer to ecology below).

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%; line-height: 1.5;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 11. Fruiting stages of C. mitis.

=Ecology=

Growth preference - Edge exploitation
<span style="font-family: Arial,Helvetica,sans-serif;"> Among all the different //Caryota// species, //C. mitis// is the only one that is commonly found in the forests where it is distributed. //C. mitis// is often found in secondary forests, and is especially abundant in disturbed areas. In addition, based on personal observations, //C. mitis// appears to be much more abundant along forest edges as compared to the interior (once again, research is underway to see if this is true!) (figure 12). This could point towards the ability of //C. mitis// to thrive along edges, where environmental conditions are harsher and more adverse.

<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;"> Figure 12. Many //C. mitis// plants along the edge of a trail in Kent Ridge Park.

Fruits of Caryota mitis - Handle with care!
<span style="font-family: Arial,Helvetica,sans-serif;"> Curiously, while the fruits contain calcium oxalate crystals that make it difficult to even handle (it causes a severe itching sensation), much less eat it, many animals have been recorded to eat the fruits of //C. mitis//. It appears that animals that feed on the fruit are less affected by the calcium oxalate crystals. //C. mitis// is also an extremely bountiful plant – based on an preliminary estimate, 124 individuals of //C. mitis// is able to produce up to over 1, 500, 000 fruits on Pulau Ubin ! However, it is important to bear in mind that the length of the branches in different individuals may vary (it can reach up to 1.5m) and this would result in different number of fruiting potential. In addition, not all flowers are bound to set fruit and this may be an overestimation. Nevertheless, there is no doubt that //C. mitis// serves as an ample food source with its luxuriant “mop” full of fruits! More research is underway for a more comprehensive study on the production of fruits by //C. mitis//.

<span style="font-family: Arial,Helvetica,sans-serif;"> The popularity of //C. mitis// fruits may be due two two factors: its year-round abundance and the energy content of the fruits. //C. mitis// appears to fruit year round as they are not constrained by environmental cues to synchronise their flowering event. Instead, the palm undergoes an initial vegetative stage to accumulate carbohydrate resources, before expending their reserves for flower and fruit production during their reproductive phase. While some botanists argue that that is a simplistic assumption and other factors may trigger flowering instead (such as accumulation of growth-substances and abiotic factors like light availability, it remains without a doubt that that //C. mitis// is a constant and prolific source of food for animals where it is commonly found. Locally, on Pulau Ubin, out of 2657 individuals, 932 individuals were in their reproductive phase !

<span style="font-family: Arial,Helvetica,sans-serif;"> In terms of energy content, it appears that //C. mitis// is fairly nutritious – the average caloric content of ripe //C. mitis// fruits is 3.36 kcal/g, comparable to that of an apple at 3.59 kcal/g. In fact, palms fruits important food resources in a tropical rainforests, and contributes to a high proportion of energy content within tropical lowland forests. By including the consideration that //C. mitis// is common in Singapore forests, this confluence of factors appear to contribute to the allure of //C. mitis// fruits as an important resource in the forests of Singapore.

Consumption of Caryota mitis
<span style="font-family: Arial,Helvetica,sans-serif;"> Various animals that have been recorded feeding on the fruits on //C. mitis//: birds, squirrels, civets and jackals. In Singapore, animals such as the long-tailed macaque (//Macaca// //fasicularis//), wild boars (//Sus// //scrofa//) , oriental pied hornbill (//Anthracoceros// //albirostris//) , and the Asian glossy starling (//Alplonis// //panayensis//) have all been recorded feeding on the fruits of //C. mitis//. Other recorded birds in Ipoh, Perak, Malaysia, that feed on the fruits are the yellow-vented bulbul (//Pycnonotus// //goiavier//), the pink-necked green pigeon (//Trenon// //vernans//) and the lineated barbet (//Megalaima lineata hodgsoni//), all of which can be found locally in Singapore. More importantly, it appears that //C. mitis// fruits are a significant food resource for the common palm civets (//Paradoxus hermaphoditus)// on Pulau Ubin.

<span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 13. An Oriental Pied Hornbill (//Anthracoceros albirostris//) (photo credit: [|Angie Ng & Hiro Machida]) and a Lineated Barbet (//Megalaima lineata hodgsoni//) (photo credit: [|Dr. Dato Dr. Amar-Singh HSS]) feeding on the fruits of //C. mitis//.

<span style="font-family: Arial,Helvetica,sans-serif;"> Furthermore, //C. mitis// is known to be the host plant for two butterflies in Singapore: the common faun (//Faunis canens arcesilas//) and the tufted jungle king //(Thauria aliris). Table 1 summarises the animals that have been recorded eating C. mitis (be it leaves or fruits) in Singapore.

<span style="font-family: Arial,Helvetica,sans-serif;"> Table 1. List of animals recorded consuming C. mitis in Singapore.
 * Common name || Scientific name || Part of plant consumed ||
 * Long-tailed macaque || //Macaca fasicularis// || Fruits ||
 * Wild boars || //Sus scrofa// || Fruits ||
 * Oriental pied hornbill || //Anthracoceros albirostris// || Fruits ||
 * Asian glossy starling || //Alplonis panayensis// || Fruits ||
 * Common palm civet || //Paradoxus hermaphoditus// || Fruits ||
 * Common faun || //Faunis canens arcesilas// || Leaves ||
 * Tufted jungle king || //Thauria aliris// || Leaves ||

Pollination
<span style="font-family: Arial,Helvetica,sans-serif;"> Palms in general area poorly studied group, and little is known about the pollination biology of many palms. However, it has been suggested that the flowers of members in the //Caryota// genus are entomophilus (attracts insects), and current research has elucidated that point. Both stingless bees and honey bees have been observed visiting the flowers of //Caryota mitis// in Singapore. More research is underway to determine what other insects visit the flowers of //C. mitis// for pollen. In addition, no bees thus far have been seen visiting the female flowers of //C. mitis//. Therefore, the pollination mechanism in //C. mitis// is still unknown and more research has to be done to determine the pollination syndrome in //C. mitis//. The bees that visit the flowers of //C. mitis// are:

<span style="font-family: Arial,Helvetica,sans-serif;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 14. Some bees that visit //C. mitis// flowers for pollen. (Photo credit: Chui Shao Xiong)
 * //Apis cerana// (figure 14)
 * //Tetragonula laeviceps// (figure 14)
 * //Tetrigona apicalis// (figure 14)
 * //Tetragonula pagdeniformis//
 * //Tetragonula geissleri//

=Human uses= <span style="font-family: Arial,Helvetica,sans-serif;"> While C. mitis is considered part of the sago palms (as all //Caryota// are), it yields little sago and is not very useful for sago production. This is unlike the related species, //Caryota urens//, also known as the Toddy palm. As the name suggests, the sap of the palm is tapped and used to make palm sugar or fermented to produce toddy. <span style="font-family: Arial,Helvetica,sans-serif;"> In addition, //C. urens// is a suitable palm for producing sago from the pith of the trunks of old trees.

<span style="font-family: Arial,Helvetica,sans-serif;"> In India, there are several uses for the palm – for food, starch is extracted from the stem and the palm heart can be eaten; for construction, the leaves are used for thatching of roofs and can also be weaved into household items, while the fibres from the leaf sheath are used for making ropes; for ornamental purposes, the seeds can be made into beads. The fuzz from young leaves are also used as tinder in some Southeast Asian countries.

<span style="font-family: Arial,Helvetica,sans-serif;"> The most popular use of this palm today would probably be for cultivation. It is widely cultivated today and due to its clustering growth habit and smaller stature, it is more popular as compared to other palms in the //Caryota// genus.

=Full Species Description of Caryota mitis= <span style="font-family: Arial,Helvetica,sans-serif;"> Refer to below for a complete description of //C. mitis// :

__Male flowers__: Very numerous about 1cm long, elongated, light to dark purple in colour, 3 petals, many stamens (yellow) __Female flowers__: Only develops after the male flowers have fallen off, smaller than males, sepals rounded, petals 3, pink to brownish in colour, yellowish or whitish tips, 3 stigma, ovary roundish ovate || Multiple inflorescence on a stem || 1-2cm in diameter, green when unripe, red to purple when ripe, subglobose (round), usually 1 seeded, contains oxalate crystals ||
 * **Stem** |||| **Leaves** ||
 * 5-15cm in diameter; ringed; green, brown or greyish; unarmed (without spines) || [[image:Unarmed stem of C. mitis.jpg width="276" height="306"]] || 5-12 per stem; spreading; bipinnate (characteristic feature); petiole 50-200cm long; rachis 1-4m long; pinnae 7-23 on each side of rachis, 50-120cm long; 7 – 23 leaflets on each side, 20x13cm in size, broadly triangular, apical margins jaggedly toothed (lending it the fishtail-like form) || [[image:Bipinnate (3).JPG width="310" height="313"]] ||
 * **Inflorescences** |||| **Fruits** ||
 * 4-7 spadices, initiating at the top and moving down stem (basipetal), interfolia or intrafolia, pendulous, 1-1.5m long; peduncle 30-45cm long; rachis 5-45cm long, rachillae 10-60, 10-65cm long, drooping

|| =<span style="font-family: Arial,Helvetica,sans-serif;">DNA Barcoding = <span style="font-family: Arial,Helvetica,sans-serif;"> //Caryota mitis// belongs to the tribe Caryoteae (subfamily Coryphoideae), which includes the following three genera: //Caryota, Arenga// and //Wallichia.// Notably, species delimitation in //Caryota// is difficult due to complex morphological differences in the leaves and inflorescence, which is compounded by the difficulty in collecting specimens due to the large dimensions in many species of the genus (//C. no, C. urens, C. gigas// etc.). The notoriety of //Caryota// stems from the relative scarcity of materials in herbaria, making traditional alphataxonomy difficult.

<span style="font-family: Arial,Helvetica,sans-serif;"> In a relatively recent experiment (2011), it appears that DNA barcoding is a useful tool for palm taxonomists with reference to the Caryoteae tribe. Within the Caryoteae tribe, to augment species identification accuracy, it appears that three DNA markers: matK, rbcL and nrITS2 are especially useful - it has a 92% species discrimination rate. This is considered high for a barcoding experiment. While //Caryota mitis// may not be a difficult species to identify in Singapore (it is the only //Caryota// species), it has a wide geographical distribution, therefore it may be misidentified as //Caryota monostachya// (also a clumping species distributed from China to Vietnam). The key distinction between the two species if that //C. monostachya// forms unbranched inflorescences (figure 15), while that of //C. mitis// is branched (figure 9 or full species description). Therefore, DNA barcoding may still be useful for species identification when no reproductive organs are available for analysis.

<span style="font-family: Arial,Helvetica,sans-serif;">Figure 15. Unbranched inflorescence of //C. monostachya//. (Photo credit: [|kylecawazafla]) =<span style="font-family: Arial,Helvetica,sans-serif;">Molecular Systematics of Caryota = <span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%; line-height: 1.5;"> <span style="font-family: Arial,Helvetica,sans-serif;"> Figure 16. Summary phyloheny for the species of //Caryota// (9 out of 13 species), with geographic distributions indicated. The tree is rooted with the other genera in the Caryoteae tribe - //Arenga// and //Wallichia.// The three major clades //(Rumphiana// clade, //Mitis// clade and //Maxima// clade) are identified based on molecular characters but are consistent with morphological features. (Image take from [|Hahn and Sytsma, 1999 - Molecular systematics and biogeography of the Southeast Asian genus Caryota (Palmae) in Systematic Botany 24(4): 558-580]).

<span style="font-family: Arial,Helvetica,sans-serif;"> Based on cpDNA, Hahn and Sytsma (1999) identified three principle clades: the //Rumphiana// clade, the //Mitits// clade and the //Maxima// clade (figure 16-17).

<span style="font-family: Arial,Helvetica,sans-serif;"> The first clade, the //Maxima// clade, consists of //C. maxima//, //C. obtusa// and //C. bacsonensis//. These three species are similar morphologically: they have solitary growth habits (does not cluster), yellow petals (versus purple petals in C. mitis), red fruits and spinose (spiny) pollen. Their distribution are limited to the Asian continent and Sumatra and Java.

<span style="font-family: Arial,Helvetica,sans-serif;"> The second clade, the //Mitis// clade, consists of most sampled //C. mitis//, one //C. monostachya// and one //C. bacsonensis//. Considering that //C. bacsonensis// was from Cuc Phuong, Vietnam, along with //C. monostachya//, it could be that the //C. bacsonensis// was a result of the hybridization with //C. monostachya//. //C. mitis// and //C. monostachya// are fairly similar morphologically, as previously discussed: they have clustering growth habits, purple petals and maroon or purple fruits.

<span style="font-family: Arial,Helvetica,sans-serif;"> The third clade, the //Rumphiana// clade, consists of //C. cumingii//, //C. no//, //C. rumphiana// and one //C. mitis//. Besides the //C. mitis// (likely the result of hybridization), all these species have solitary stem growth habit, purple petals and fruits, and clavate (club-like) pollen processes.

<span style="font-family: Arial,Helvetica,sans-serif;"> The pairing of the //Mitis// and //Rumphiana// clades are consistent with morphological characters (pollen morphology – clavate, petal and fruit pigmentation – purple and stamen number – 6 to 75), despite not having strong support based on the shortest equally and differentially-weighted Wagner parsimony analyses and minimum evolution analyses and a Dollo parsimony analysis nullifies this relationship. Therefore, Hahn and Sytsma (1999) considers it the best supported intrageneric relationship topology <span style="font-family: Arial,Helvetica,sans-serif;">.

<span style="font-family: Arial,Helvetica,sans-serif; line-height: 0px; overflow: hidden;">[[image:maps.png width="975" height="313"]]
<span style="font-family: Arial,Helvetica,sans-serif;">Figure 17. Distribution of the three clades - //Maxima// clade, //Mitis// clade and //Rumphiana// clade. <span style="font-family: Arial,Helvetica,sans-serif;">(Image take from [|Hahn and Sytsma, 1999 - Molecular systematics and biogeography of the Southeast Asian genus Caryota (Palmae) in Systematic Botany 24(4): 558-580]).

<span style="font-family: Arial,Helvetica,sans-serif;">Summary model of evolution in Caryota
<span style="font-family: Arial,Helvetica,sans-serif;"> In Southeast Asian biogeography, two interpretations predominate the discussion of biological distribution – vicariance due to tectonic events or sea level changes or dispersal events that helped extend the distribution of the species in question. In //Caryota,// it is likely that a both mechanisms were invoked concurrently based on the three clades. The distribution of the three clades correlates well with vicariance and the geologic history of SE Asia. However, a full account of the distribution and evolutionary history of Caryota requires the consideration of dispersal to explain the deviation from the correlation between vicariance and geologic history with the relationship between the three clades.

<span style="font-family: Arial,Helvetica,sans-serif;"> The model of evolution as proposed by Hahn and Sytsma (1999) is as follows: there was an original, common ancestral species resembling that of the //Maxima// clade on mainland SE Asia. This was followed by two separate episodes of cladogenesis, based on habitat preference shifts, morphological evolution, and range expansion due to vicariance and dispersal.

<span style="font-family: Arial,Helvetica,sans-serif;"> Considering that //C. maxima// is a species that is limited to higher elevations, the first cladogenic event be the invasion of the lowlands and shifts in floral and fruiting biology as per the //Mitis// and //Rumphiana// clade. The clustering growth form may also be indicative of the colonization of the understory by the //Mitis// clade.

<span style="font-family: Arial,Helvetica,sans-serif;"> The second cladogenic event would be the evolution of the //Rumphiana// clade, a different track from that of the clustering growth habit of the //Mitis// clade. Given the uncharacteristically wide distribution of //C. rumphiana//, it is probable that dispersal was a critical factor in the evolution of the //Rumphiana// clade. The exception of this clade lies with //C. no//, an endemic species of Borneo. It is more likely the result of speciation and cladogenesis due to vicariance of Borneo and Sulaweisi, and less likely due to dispersal.