During one of my recent trips along the Treetop Walk trail on 27 September, I came across a flowering Leaf Litter Plant. This relatively common understorey forest plant was quite easy to identify with its unique overall appearance. This was the first few rainforest plants that I had managed to identify in the early days when I started out to explore the wild side of Singapore.

Upon close observation of the flowering stalks of the Leaf Litter Plant, I found a few tiny caterpillars on the stalks. They appeared to be feeding on the flowers and young fruits.

While updating its pictures in my website with those from my recent trip, I did a quick online search on this plant to check whether there was anything new on it that was shared recently. Interestingly, NParks Flora & Fauna Web had updated its accepted botanical name to Agrostistachys sessilifolia instead of Agrostistachys borneensis (which I and others had used for years). Agrostistachys borneensis was indicated as its synonym with the text “auct. non” after the name. This basically denoted that Agrostistachys borneensis was a misapplied name of this plant in the past.

The change aligned to the name listed in the 2022 Singapore flora checklist. In the checklist, there were 2 Agrostistachys species listed, namely Agrostistachys gaudichaudii and Agrostistachys sessilifolia. As Agrostistachys gaudichaudii was assessed to be extinct locally, the Agrostistachys species that was still thriving in the wild should logically be Agrostistachys sessilifolia. I was unable to find any report that explained how the misapplied name was being discovered but it was quite obvious when I saw the pictures of Agrostistachys borneensis displayed in the Flora of Sri Lanka and Flora of Peninsular India websites assuming they were the authentic version.

As of this note, the name Agrostistachys borneensis was still being used in many of the websites as the accepted botanical name of this plant since it was still in the early days where the change had taken place. Historically, another name Agrostistachys indica was being described in a 2013 publication that consolidated 100 common plants found in the Nee Soon Swamp Forest [1]. Both Agrostistachys borneensis and Agrostistachys indica were listed in a Nee Soon Swamp Forest plant checklist published in the same year [2]. In addition, the name Agrostistachys borneensis was also used in a plant checklist of Bukit Timah Nature Reserve published in 2011 [3] and the biodiversity survey of the same Reserve published in 2019 [4].

In iNaturalist website (viewed on 13 October 2024), there were 26 observations of Agrostistachys sessilifolia with most of the records (23 of them) from Singapore. The remaining 3 records were from Malaysia. The records from Singapore were only uploaded from April 2022 onward, likely an effect from the latest published plant checklist. On the other hand, there were 18 observations on Agrostistachys borneensis from Singapore with the most recent sighting in January 2023. Based on the 2022 Singapore flora checklist, all these records should be updated to Agrostistachys sessilifolia.

The used of the name Agrostistachys sessilifolia in local published materials before 2022 that I could find was only from a book published by the then Raffles Museum of Biodiversity Research in 2012 (page 94) on Singapore's rainforest [5].

References:

[1] Tan SY, Koh CY, Siow HJM, Li T, Wong HF, Heyzer A, Tan HTW. 100 Common Vascular Plants of the Nee Soon Swamp Forest, Singapore. 2013. | Read article |

[2] Wong HF, Tan SY, Koh CY, Siow HJM, Li T, Heyzer A, Ang AHF, Ismail MR, Srivathsan A, Tan HTW. Checklist of the Plant Species of Nee Soon Swamp Forest, Singapore: Bryophytes to Angiosperms. 2013. | Read article |

[3] Turner IM, Chua KS. Checklist of the Vascular Plant Species of the Bukit Timah Nature Reserve. 2011. | Read article |

[4] Ho BC, Lua HK, Ibrahim B, Yeo RSW, Athen P, Leong PKF, Ibrahim A, Koh SL, Ibrahim H, Lindsay S, Chin LL, Seah WW, Middleton DJ. The plant diversity in Bukit Timah Nature Reserve, Singapore. Gardens’ Bulletin Singapore 2019;71(Suppl. 1):41-134. | Read article |

[5] Wang LK, Yeo DCJ, Lim KKP, Lum SKY. Private Lives: An Expose of Singapore's Rainforests. Raffles Museum of Biodiversity Research, Singapore. 2012.