All across Singapore, a special plant lives almost unnoticed. It goes by many names, depending on who you ask. In English, it is commonly known as 'summer cilantro’ or ‘Bolivian coriander’, but the Porophyllum ruderale (Jacq.) Cass. is also known as pápalo or pápaloquelite in Mexico, quirquiña or quilquiña in Bolivia, and yerba porosa all over Latin America. The name pápaloquelite derives from Nahuatl, a language used by the Aztec civilization and which is still spoken by 1.5 million people in Mexico.¹ It is a composite word made up of papalotl (butterfly) and quilitl (edible herb), ultimately meaning ‘edible butterfly’.² While this plant is native to Mexico and Central and South America, it has now been naturalised in Singapore.³ This means that its population is self-sustaining without the need to introduce new individuals,⁴ enabled by the easy dispersal of its seeds by the wind.

In Singapore, pápalo has been recorded specifically in a scrubland near Tanah Merah,⁵ in a grassland in Punggol Barat,⁶ and in Pulau Tekukor,⁷ though it can also be found in many other parts of the island.⁸ When flowering, the species produces flower-heads or capitula that measure about 1.5–2.5 cm in length. Each of these flower-heads contains around 15 to 30 tiny flowers. After the flowers are pollinated successfully, the seeds develop, well hidden within the green colored bracts (also known as phyllaries) till they are fully mature. When the seeds are ready for dispersal, the phyllaries will open up fully to expose the tiny seeds, each armed with a tuft of hairs that allows them to be carried along with the breeze, much like the way dandelions from temperate areas are dispersed. ⁹ Pápalo can sometimes be confused with the plant Emilia sonchifolia (L.) DC., or the 'Cupid's Shaving Brush', which is native to Asia. They can be differentiated, however, by the shape of their leaves and the colour of their buds. Pápalo is an upright herb with elliptical leaves that grows up to 1 m in height and often resembles a small shrub due to its stature. Emilia sonchifolia is a herb that has a distinct basal rosette of leaves, which is absent in P. ruderale, and E. sonchifolia also has leaves displaying different ranges of shapes depending on their position on the plant. The flowers of E. sonchifolia are also smaller than the other species and come in various shades of pink or reddish-purple, whereas the flowers of the pápalo plant are white or off-white.¹⁰

Where it comes from, pápalo is put to work. In Mexico, it is eaten and acts as a key ingredient in significant regional recipes. In pre-colonial times, the diet of cultures that lived in what is now Mexico consisted primarily of corn, beans, chillies, and squash, which were grown together in la milpa, a traditional form of agriculture.¹² The different weeds and herbs that grow amongst these key crops, quelites, were also eaten. Pápalo is one of these, meaning that its flavour, which is somewhat reminiscent of arugula and spinach, has been part of the Mexican palate for many centuries. It is a great ingredient to add to a salsa verde (green salsa) or guacamole, and it may even be added fresh to tacos or soups as a final tasty touch. Pápalo is particularly important in the state of Puebla, in Central Mexico, where it is an indispensable ingredient for cemitas. Cemitas are a kind of torta—a type of sandwich that is common in all of Mexico and is similar to Vietnamese bánh mì—that is endemic to the state of Puebla. Cemitas typically have pápalo, avocado, quesillo or string cheese, tomato slices, onion, chipotle or other kind of chilli, and meat, usually breaded chicken.¹³ These tortas are typically prepared using recipes passed down through multiple generations and are understood to be ubiquitous in Puebla, where they have become so entrenched in the regional gastronomical identity that they transcend class divisions and other social fractures.¹⁴

Likewise, in both Mexico and in South America, pápalo is known to have medicinal uses. Not only is it understood to reduce cholesterol and improve digestion when eaten, but is also used in different preparations to treat a variety of issues.¹⁵ In some parts of Mexico, it is used as a natural anti-inflammatory medicine, and may even be used to fight tooth aches.¹⁶ It is also used by Indigenous communities in the south of Mexico to help regulate the body after experiencing ataques or latidos, which are local cultural terms to describe experiences similar to irregular heart beatings or even epileptic convulsions.¹⁷ In some parts of the south of Mexico, pápalo is also boiled whole and given to women after they have given birth with which to wash themselves. This is supposed to help regulate their menstruation during the postpartum period.¹⁸ In Bolivia, similarly, pápalo is known to be an anti-inflammatory plant. It is used to treat burns¹⁹ or, in some cases, water infused with pápalo can also be drunk to treat a sore throat.²⁰ And beyond its medicinal use, pápalo is also employed in many creative ways, such as perfumes, drinks, or even pesticides.²¹ Its essential oils have been researched as a molluscicidal and larvicidal option, including against the larvae of the dengue vector Aedes aegypti mosquito.²² Outside of Latin America, pápalo has also become a popular species for home cultivation, as is the case in Europe and North America.²³

In Singapore, however, there are currently no reported uses for pápalo, be they economic, cultural, or of any other kind. The only trace of pápalo used by humans is in the Singapore Atlas Bar, located inside the Raffles Hotel, which features one bottle of 'La República' in their gin collection. Theirs is allegedly the largest gin collection in the world.²⁴ La República is produced in Bolivia and uses pápalo to enhance its flavour profile. Outside of that, pápalo is nowhere to be found. So, if pápalo is not imported to Singapore for any specific purpose, and it is native to ecosystems located on the other side of the world, how did it even get here? Who brought it here, and to what end?

Today, this is a mystery. No one really knows. The first reports of pápalo being introduced to Southeast Asia are from 1945 in Bogor, Indonesia,²⁵ but there are no records on the reasons it was there in the first place. We may speculate it could have been imported to Indonesia to introduce it to the Bogor Botanical Gardens, which are home to over 3,000 species from all over the world,²⁶ but there is no reported trace of pápalo being part of the Bogor Botanical Gardens either. The first recorded introduction of pápalo to a herbarium in Southeast Asia was three decades later in Sumatra, in 1978.²⁷ Its introduction to the region could also have been accidental, as it is believed to have been the case in the Galapagos Islands,²⁸ where pápalo has been reported since 1999.²⁹ It is suspected that it was introduced as food into the islands before it accidentally spread into the wild.³⁰ Its seeds are light and can be carried by the wind, after all. Another possibility is that it was traded from Veracruz, Mexico—where it can be commonly found in food markets—to the Philippines, given that this was the trade route of the Manila Galleon, but there are no reports of pápalo being involved in this trade.

Pápalo was first reported in Singapore in 1992³¹ and subsequently in 1995,³² but its arrival story is also unclear. And, given the lack of uses allocated to it in Singapore (as opposed to the regions to which it is native), it seems like not many have even noticed the opportunities that pápalo presents. This is not particularly rare: it is well reported that globalisation, migration, and the overall dispersal of plant species all over the world leads in most (though not all) cases to a loss of ‘biodiversity-based cultural knowledge’, and Singapore is no exception.³³ Pápalo has not yet begun its social life in Singapore. So far, only a few botanists and plant enthusiasts are aware of its existence, spotting it in several corners of Singapore and in some cases capturing its beauty in full display.³⁴ Some birds have also noticed, using it as an occasional perching site and picking its dried fruits for nesting material.³⁵

But pápalo has so much more to offer. For traditional medicine enthusiasts, it could open new horizons in its interactions with Ayurvedic practices or even Traditional Chinese Medicine. Hybrid expressions of traditional medicine are common all over Southeast Asia,³⁶ and the introduction of elements that are meaningful to traditional medicine from other parts of the world can only enrich Singapore’s landscape. Likewise, from a culinary point of view, pápalo presents an opportunity. It brings with it new flavours. Whether it is by finding pápalo herbs to experiment with at home, or by incorporating pápalo into the ingredients used at Mexican and South American food places in Singapore, this plant can only be an exciting new experience for enthusiasts and non-enthusiasts alike. In Singapore, pápalo is an opportunity that is yet to be explored. Above all, this plant is an important reminder to maintain an attitude of openness and curiosity towards the unknown. Pápalo remains an anonymous weed for most people in Singapore, but it has been a culturally significant plant for people on the other side of the Pacific Ocean for millennia. The teaching of the pápalo is rather simple: We never know what the seemingly random herbs that grow besides us might have to offer.