Sea Apple Tree. For the Sea Apple Cucumber, see Pseudocolochirus voilaceus.

“The clearest way into the Universe is through a forest wilderness.” – John Muir
external image Photo%203-11-16%204%2036%2051%20PM.jpgexternal image s_grande1.jpgFigure 1 (Left): Underside of a Syzygium grande crown at the Singapore Botanic Gardens. (Photograph by Tan WA Lorraine)


Introduction

Syzygium grande (Wight) Walp. is a species that belongs to the family Myrtaceae. In the Malesian biogeographical region, there are 35 genera of Myrtaceae and Syzygium is the most abundant in species [1]. This includes species like Syzygium aromaticum, the popular spice commonly known as clove.
Syzygium grande can be found throughout the tropical Asia in a large variety of habitats [2,3]. This includes coastal forest, where it can be commonly found in Singapore. Syzygium grande is also cultivated in Singapore as a roadside ornamental tree [3]. The common name is Sea Apple, with other names such as Jambu Laut or Jambu Air Laut [4]. Capable of growing up to 30 m in height, one towering individual in Sentosa has also been awarded the Heritage Tree status.

Although it is Common in Singapore, S. grande is a species that is part of the natural heritage in Singapore [5]. This page aims to encourage an appreciation for the biology, value, and taxonomic history of S. grande as a part of our native flora.


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Biology

Distribution

Native Distribution:
Thailand, India, Sri Lanka, Burma, Indo-China, Malaysia, Singapore, Borneo [2]

Worldwide distribution:
external image 20m?map=Syzygium+grande
Figure 2: Global distribution of Syzygium grande from the Encyclopedia of Life [6].
Syzygium grande is an introduced species in the New World Tropics but has one native species in Hawaii [6,7]. According to the IUCN Red List, S. grande has been listed as one of its accepted synonyms, Syzygium firmum. Syzygium firmum is considered Vulnerable, but the range description only includes Sri Lanka and needs updating [8].


Description


Large tree up to 30 m tall and 80 cm in diameter. Dense crown, dark and glossy with oblong shape [3].
external image s_grande1.jpg
Cultivated S. grande along a road side.
The flowers are up to 3 cm across, white, and sessile [2]. Each flower has many stamens about 10 mm long and one 9–15.4 mm style exceeding them.

Up to 14 cm long inflorescences can be found at the base of a leaf stalk, or at the ends of its branches [3]. The flowers are also very strongly fragrant [4].
external image s_grande4.jpgFlowers of S. grande and the downturned leaves.
external image 1567283001_ef1932c194_b.jpgClose-up of a flower by Photos of NUS Toddycats, ICCS, and LKCNHM on Flickr

It produces fleshy fruits that are ellipsoid, about 4 cm long and 3 cm wide that are green when ripe [3,4]. Each fruit has a prominent 6mm diameter apical calyx rim and one seed [3].
external image s_grande5.jpg
Ripe fruits of S. grande.
It has simple, opposite, stalked leaves that are broadly elliptic, about 16 cm long and 9 cm wide [2,3]. The leaves are darker green above, lighter green below, and each has a down-turned leaf tip. Two intramarginal veins run parallel to the leaf margin, with 9–16 pairs of side veins [2].
external image Sgrandearrow.pngSenescent leaf showing the distinct intramarginal vein, edited from uforest.org

external image Scale%20edit.jpg
Leaves of a seedling showing the leaf arrangement. (Photograph by Tan WA Lorraine)
The bark is pale-grey to pink-brown, becoming cracked and flaky with age [3]. The base of the trunk is fluted but are not truly buttressed [4].
external image Trunk.jpg
Trunk of an individual from the Singapore Botanic Gardens. (Photograph by Tan WA Lorraine)
There are two varieties of S. grande, S. grande var. grande and var. parviflorum. Syzygium grande var. parviflorum differs from the former with generally smaller flowers. It is only known from the type locality and from Sabah.

Ecology

Syzygium grande can be found in habitats which include: bamboo forest, savannah, edges of evergreen forest and coastal forest [2,3]. It is a perennial which grows relatively quickly and generally flowers and fruits from March to May in Singapore, with exceptions [4]. As the seeds are common and germinate readily, the species helps with natural regeneration [9].

The fruits are eaten by bats which helps with their dispersal [9]. Syzygium grande is also the caterpillar host plant for butterflies species such as the Centaur Oakblue (Arhopala centaurus nakula) and the Plain Plushblue (Flos apidanus saturatus) [10,11].
With birds, a Thai study in Khao Yai National Park found that although Syzygium spp. (as Eugenia) trees represented only 3% of all large trees in 302 sample plots, they managed to garner 26% of the hornbill nests recorded [12]. Knowing the range and habit of S. grande, S. grande could be included in this observation and be beneficial to the local species of hornbill in Singapore.
Another bird association that has been observed is with Red-breasted Parakeets (Psittacula alexandri) in Singapore, where they have been observed to eat the flowers of S. grande.

Uses

The trunk is used as timber, a medium hard wood known as ‘Kelat’ [9]. It is also an ornamental tree that was planted as a roadside tree in Singapore to act as fire breaks from lalang fires [3]. Recently, to reduce the risk of branch falls [13], roadside S. grande trees have been replaced by a shorter species (up to 20 m) Tristaniopsis whiteana, or River Tristania.

More information on the ornamental uses and cultivation of S. grande can be found here.

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Taxonomy

Classification

  • Kingdom: Plantae
  • Phylum: Tracheophyta
  • Class: Magnoliopsida
  • Order: Myrtales
  • Family: Myrtaceae
  • Genus: Syzygium
  • Species: Syzygium grande
[8]

Origin of Name

Greek syzygos, joined, referring to the paired leaves of this genus; Latin grandis, great, referring to the large leaf and flower bud [3].


Name and Type

Syzygium grande (Wight) Walp. was originally described as Eugenia grandis Wight (1841) [14] as seen in Figure 3.

external image Wight%201841.jpg
Figure 3: Description of Eugenia grandis Wight. Taken from the Biodiversity Heritage Library.

There was no specific holotype assigned in the original description, with the given information only listed as “Mergui—Griffith Silhet”. As such, a lectotype was designated by Byng et al. [15] with the details as follows: “—BURMA [Myanmar]. Mergui, Griffith s.n. (K! [barcode K000821429]; isolectotype P! [barcode P05208756])”.

The accepted name was given by Walpers in 1843 [16].

Synonyms

The synonyms were taken from The Plant List ver 1.1:
  1. Eugenia cymosa Roxb. (Illegitimate)
  2. Eugenia grandis Wight
  3. Eugenia laosensis Gagnep.
  4. Eugenia laosensis var. quocensis Gagnep.
  5. Eugenia montana Wight (Illegitimate)
  6. Jambosa firma Blume
  7. Jambosa grandis (Wight) Blume
  8. Syzygium firmum (Blume) Thwaites
  9. Syzygium gadgilii M.R.Almeida (Illegitimate)
  10. Syzygium grande var. parviflorum Chantaran. & J.Parn.
  11. Syzygium laosense (Gagnep.) Merr. & L.M.Perry
  12. Syzygium laosense var. quocense (Gagnep.) H.T.Chang & R.H.Miao
  13. Syzygium megalophyllum Merr. & L.M.Perry
  14. Syzygium montanum Thwaites & Hook.f.
  15. Syzygium tamilnadensis Rathakr. & V.Chithra (Illegitimate)

Roxburgh described the species in 1832 as Eugenia cymosa, before Wight [17]. This description was deemed illegitimate because the name Eugenia cymosa was already used by Lamarck in 1789 for Syzygium cymosum (Lam.) DC. [18]. This is why Wight’s description contains Roxburgh’s name for the species as Eugenia cymosa non Lam..

Eugenia-Syzygium split

Syzygium Gaertn. [19] is the largest genus in the Myrtaceae and has about 1200 species of evergreen trees and shrubs in the Old World tropics and subtropics [3]. Separating species has been difficult due to few diagnostic characteristics and great variability [20]. There has also been much confusion because many Syzygium species were originally described under the Neotropical genus Eugenia.

Merrill and Perry were the first to provide prominent modern research for the taxonomic revisions of Eugenia L. and Syzygium Gaertn. [21]. It was only more than 30 years later that this argument gained more ground, when Schmid provided strong floristic evidence to separate the two genera [22]. Even then, there was practical difficulty in telling apart the leaves, making the trend unpopular [4]. In molecular data, Gadek et al. were the first to use matK data to show the separation of the Asian Syzygium from the Neotropical Eugenia [23]. Their analysis showed that Syzygium is separate from the Myrtoidae clade which Eugenia belongs to, with bootstrap certainty of 52%. This, coupled with molecular and morphological data from many other studies, has led to the conclusion that the separation is fact [7].
As molecular analyses grew in frequency, Soh and Parnell were able to focus on Syzygium in greater detail [24]. In their study, they investigated the phylogenetic relationships of subgenera within the Syzygium genus. Through analysing DNA sequences (ETS and ITS) and leaf morphology, they were able to generate a strict consensus tree from eight of the Most Parsimonious Trees (MPTs) (Figure 4). This tree has higher bootstrap support than the analysis of the DNA evidence alone. However, the exact relationships between S. grande and the closely related species are still unclear due to the polytomy.
Syzygium cumini is also a tree that can be found in tropical Asia, but it is an exotic that has been introduced in Singapore [25]. The other species have distributions restricted to mainland Southeast Asia [26].
external image Soh%20and%20Parnell%20S.grande%20tree%20ITS%20and%20morphological.jpg
Figure 4: Strict consensus tree of eight MPTs retrieved from the combined analysis of ETS, ITS and morphological data. Bootstrap values >50% are indicated above the branches. Bayesian posterior probabilities are indicated below the branches. Dashed line indicates alternative branching retrieved from Bayesian analysis. Adapted from Soh and Parnell [24].

Future Work

For future work in the Syzygium genus, Parnell et al. [7] predicts that there will be a lot of logistical difficulty. There is currently insufficient data for such a species rich, widespread and poorly known genus. Molecular data has been limited on the reliability of genes and phylogenetically important morphological data (such as leaf anatomy [24]) are still being discovered. These limit understanding what drives diversification in Syzygium and the different breeding mechanisms of the species.

Their work also showed that it may be operationally unfeasible to adhere strictly to the concept of monophyly [7]. Variation patterns of Syzygium in Southeast Asia differ from Australasia partly due to different breeding systems, making applying a uniform species concept difficult. From this arises the debate among taxonomists for what is "sufficient mass" to justify the possibility of splitting the very large Syzygium into smaller genera. As such, there is a lot of potential in looking into the genus and S. grande would be part of the scrutiny in years to come.
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References

  1. van Balgooy (1998) Malesian seed plants: Portraits of tree families. Volume 2. Rijksherbarium/Hortus Botanicus. 307 pp.
  2. Parnell J & Chantaranothai P (2002) Myrtaceae. In: Santisuk T & Larsen K (eds.) Flora of Thailand. Volume 7 Part 4. The Forest Herbarium, Royal Forest Department, Bangkok, Thailand. Pp. 778–914.
  3. Ashton PS (2011) Myrtaceae. In: Soepadmo E, Saw LG, Chung RCK & Kiew R (eds.) Tree Flora of Sabah and Sarawak. Volume 7. Forest Research Institute Malaysia. Pp. 87–330.
  4. Corner EJH (1988) Wayside trees of Malaya. Third edition. Volume 2. Malayan Nature Society, Kuala Lumpur. 861 pp.
  5. Chong KY, Tan HTW & Corlett RT (2009). A Checklist of the Total Vascular Plant Flora of Singapore: Native, Naturalised and Cultivated Species. Raffles Museum of Biodiversity Research, National University of Singapore, Singapore. 273 pp.
  6. Renu G, Thilakar SJ & Narasimhan D (2013) Syzygium grande. Encyclopedia of Life. http://eol.org/pages/2508659/data (Accessed 22 November 2016).
  7. Parnell JAN, Craven LA & Biffin E (2006) Matters of Scale: Dealing with One of the Largest Genera of Angiosperms. In: Hodkinson TR & Parnell JA (eds.) Reconstructing the tree of life: taxonomy and systematics of species rich taxa. CRC Press, Boca Raton, Florida. Pp. 251–273.
  8. World Conservation Monitoring Centre (1998) Syzygium firmum. The IUCN Red List of Threatened Species 1998: e.T30877A9578563. http://www.iucnredlist.org/details/30877/0 (Accessed 7 November 2016).
  9. Rao AN & Wee YC (1989) Singapore trees. Singapore Institute of Biology, Singapore. 357 pp.
  10. Tan H (2011) Life History of the Centaur Oakblue. Butterflies of Singapore. http://butterflycircle.blogspot.sg/2011/01/life-history-of-centaur-oakblue.html (Accessed 21 November 2016).
  11. Tan H (2009) Life History of the Plain Plushblue. Butterflies of Singapore. http://butterflycircle.blogspot.sg/2009/12/life-history-of-plain-plushblue.html (Accessed 21 November 2016).
  12. Poonswad P (1995) Nest site characteristics of four sympatric species of hornbills in Khao Yai National Park, Thailand. Ibis, 137(2): 183191.
  13. Hoe PS (2013) Some tall trees being replaced to reduce risks. The Straits Times, 19 May 2013. http://www.straitstimes.com/singapore/some-tall-trees-being-replaced-to-reduce-risks (Accessed 21 November 2016).
  14. Wight R (1841) Illustrations of Indian botany. Volume 2. J.P. Pharaoh, Madras. http://biodiversitylibrary.org/page/10415487 (Accessed 7 November 2016).
  15. Byng JW, Wilson P & Snow N (2015) Typifications and nomenclatural notes on Indian Myrtaceae. Phytotaxa, 217(2): 101–116.
  16. Walpers WG (1843) Repertorium Botanices Systematicae. Volume 2. F. Hofmeister, Leipzig. 1029 pp.
  17. Roxburgh W (1832) Flora Indica: or, descriptions of Indian plants. Volume 3. Serampore: printed for W. Thacker and Co. Calcutta, and Parbury, Allen and Co. London. 875 pp.
  18. Lamarck JB (1789) Encyclopédie méthodique: botanique. Volume 3. Paris, Liège, Panckoucke, Plomteux. 754 pp.
  19. Gaertner, J (1788) De Fructibus et Seminibus Plantarum. Volume 1. Academiae Carolinae, Stutgardiae. 577 pp.
  20. Byng JW (2013) Systematics of Syzygium (Myrtaceae) from Africa and the Indian Ocean Region. Unpublished PhD Thesis. University of Aberdeen, Scotland. 296 pp.
  21. Merrill ED & Perry LM (1939) The myrtaceous genus Syzygium Gaertner in Borneo. Memoirs of the American Academy of Arts and Sciences, 18(3): 135–202.
  22. Schmid R (1972) A resolution of the Eugenia-Syzygium controversy (Myrtaceae). American Journal of Botany, 59(4): 423–436.
  23. Gadek PA, Wilson PG & Quinn CJ (1996) Phylogenetic reconstruction in Myrtaceae using matK, with particular reference to the position of Psiloxylon and Heteropyxis. Australian Systematic Botany, 9(3): 283–290.
  24. Soh WK & Parnell J (2011) Comparative leaf anatomy and phylogeny of Syzygium Gaertn. Plant Systematics and Evolution, 297: 1–32.
  25. National Parks Board (2013) Syzygium cumini (L.) Skeels. Flora and Fauna Web. https://florafaunaweb.nparks.gov.sg/Special-Pages/plant-detail.aspx?id=3158 (Accessed 22 November 2016).
  26. The Plant List (2013) Version 1.1. http://www.theplantlist.org/ (Accessed 22 November 2016).

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