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Short Notes on Nature Singapore

8 July 2018 | Unknown Dioscorea Species |

When I first saw this unknown Dioscorea species hanging from another plant by the side of a road in January, it did not appear to be something that worth further investigation. Similar-looking Dioscorea species had been seen in a nearby park and I had assumed it to be Dioscorea pyrifolia. Furthermore, it was unlikely to get to an accurate identity based on the characteristics of the leaf alone.

Things got more interesting when I saw “fruits” hanging from the leaf axils along the climbing stem. These so call “fruits” were actually the bulbils which are buds produced in leaf axils that can give rise to new plants. The climber appeared to be quite fertile judging from the numerous bulbils available. I collected 2 of the elongated bulbils and placed them in a pot. Until today which was about 5 months, there was still no sign of any new plant from them.

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In the Singapore flora checklist published in 2009, there were 10 Dioscorea species listed. Two of them indicated as extinct were Dioscorea stenomeriflora and Dioscorea tenuifolia. A search in the NParks' Flora & Fauna Web yielded the names of 5 species. One of the species in there, Dioscorea alata was not listed in the 2009 flora checklist. However, the website did not list the commonly available Dioscorea bulbifera. Over at the Biodiversity of Singapore website, 8 species with their pictures were on display. Of interest was Dioscorea orbiculata var tenuifolia indicated as recently rediscovered which I assumed was Dioscorea tenuifolia listed in the 2009 flora checklist. Although Dioscorea laurifolia was assigned a common status in the flora checklist, it was no recorded in both websites.

Botanical Name 2009 Singapore Flora Checklist NParks Flora & Fauna Web Biodiversity of Singapore website
Dioscorea alata Not listed Listed Not listed
Dioscorea bulbifera Listed Not listed Listed
Dioscorea glabra Listed Not listed Listed
Dioscorea hispida Listed Listed Listed
Dioscorea laurifolia Listed Not listed Not listed
Dioscorea polyclados Listed Listed Listed
Dioscorea prainiana Listed Not listed Listed
Dioscorea pyrifolia Listed Listed Listed
Dioscorea sansibarensis Listed Listed Listed
Dioscorea stenomeriflora Listed Not listed Not listed
Dioscorea tenuifolia Listed Not listed Listed

Based on the PROSEA website, bulbils is absent from Dioscorea pyrifolia. Hence, the Dioscorea species with elongated bulbils was unlikely to be Dioscorea pyrifolia. With that, there was no further clue on its identity for the time being.

Update: 16 March 2019

The Biodiversity of Singapore website had added pictures of 2 more Dioscorea species (Dioscorea laurifolia and Dioscorea kingii) since July 2018. According to a 2018 publication [1], Dioscorea kingii is a native species that appeared to be overlooked and hence not included in the existing published plant checklists.


[1] Ho BC, Lua HK, Leong PKF, Lindsay S, Seah WW, Ibrahim B, Loo AHB, Koh SL, Ibrahim A, Athen P. New records and rediscoveries of vascular plants in Bukit Timah Nature Reserve, Singapore. Gardens' Bulletin Singapore 2018;70(1):33-55. | Read article |

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