This overdue post was drafted in June 2021. I paused posting new Nature Notes after 2020, so it remained a draft until now. The status of the plant has changed since then, and the draft has been updated accordingly.

In June 2021, I conducted my routine exploration of the nearby park, which is located in close proximity to my residence. Despite its nearness, I had not visited the park since June 2020. The visit was well worth the two hours spent on that Saturday afternoon. The weather was mild due to the cloudy conditions.

The most notable part of the walk occurred near the end when I discovered a small area recently cleared of vegetation. It appeared that some trees had fallen and were subsequently removed, exposing the ground. Various seedlings had already begun to populate this exposed area. While examining the seedlings, I encountered an herbaceous plant (Fig. 1) from the Sunflower family (Asteraceae). This plant resembled Emilia sonchifolia (Cupid's Shaving Brush) but differed in that its inflorescences exhibited a light yellow-to-orange coloration, and the plant itself was generally at least twice the size of typical Emilia sonchifolia specimens. I suspected that this might represent a new plant record for Singapore, as I had not previously encountered it.

Fig. 1: First sighting of Emilia praetermissa (Yellow Thistle) in a park in June 2021

The search for its identity was relatively straightforward. The first candidate considered was Emilia fosbergii (Florida Tasselflower), but its inflorescences are red in color. Among the image results, some pictures resembled the observed plant, leading to a publication from Taiwan [1] that identified it as Emilia praetermissa (Yellow Thistle). According to two publications from 1973 [2-3], Emilia praetermissa is likely the result of natural genetic mixing between Emilia sonchifolia and Emilia coccineae, followed by the doubling of the mixed genetic materials (chromosome).

Fig. 2: Seedlings of Emilia praetermissa (Yellow Thistle)

Previously, I was unable to find any online reports regarding its sighting in Singapore. As of 26 June 2021, the iNaturalist website recorded 361 observations of this plant, with 285 entries originating from Taiwan. This plant was first documented in Taiwan in 1997 [1]. Currently, there are 3,014 observations worldwide, with 43 of them being from Singapore. The first observation was dated September 2019 in Jurong Eco Garden.

During my observation in June 2021, numerous seedlings were already observed around the parent plant (Fig. 2). Additionally, I identified several seedlings growing among the grasses in another area of the same park. It became evident that the dispersion of this new plant had commenced. I anticipate that it is only a matter of time before this plant becomes as prevalent as the other two introduced weedy plants, Fatoua villosa (Mulberry Weed) and Erigeron bellioides (Bellorita), which I discovered in June 2015 and January 2016, respectively.

Although there have been many sightings across Singapore based on observations on the iNaturalist website, its presence has not yet been officially documented in any local publication. Given that this plant is now established, it is likely to be included in the next update to the Singapore flora checklist.

References:

[1] Chung KF, Ku SM, Kono Y, Peng CI. Emilia praetermissa Milne-Redh. (Asteraceae) - a misidentified alien species in Northern Taiwan. Taiwania 2009;54(4):385-390. | Read article |

[2] Olorode O. Identification of the Genomic Complements of Emilia praetermissa (Senecioneae-Compositae). Am J Bot 1973;60(1):55-60. | Read abstract |

[3] Olorode O, Olorunfemi AE. The hybrid origin of Emilia praetermissa (Senecioneae: Compositae). Ann Bot (Oxford) 1973;37;185-191. | Read abstract |