According to a fern survey done in 2010-2011, reported in 2014, Pleocnemia conjugata was a new fern to Singapore [1]. However, a 2015 report from Thailand seemed to indicate that the fern was discovered in Singapore since 1991 [2]. In addition, a field survey done in 2002 at the Singapore Botanic Garden had sighted this fern [3].

Reference:

[1] Tan BC, Ng-Chua ALS, Chong C, Lao C, Tan-Takako M, Ngiam ST, Tay A, Yap VB. The urban pteridophyte flora of Singapore. J Trop Biol Conservation 2014;11:13-26. | Read article |

[2] Simma R, Masuthon S, Lindsay S. Pleocnemia conjugata (Dryopteridaceae), a new record for Thailand. Thai For Bull (BOT) 2015;43:74-78 | Read article |

[3] Pui CF, Tan B. Singapore Botanic Gardens --- a safe heaven for tropical pteridophytes? 9th National Undergraduate Research Opportunities Programme (NUROP) Congress 2003.