You might think vanilla is plain, but research shows it’s anything but. Emerson Pansarin’s latest paper in Plant Ecology and Evolution reveals that a plant thought to be one Vanilla species is two. While the plants look similar, study in the field showed they grow on different host plants, and attract different pollinators. The discovery raises the possibility that Brazil, the centre of diversity for Vanilla may harbour more than the 40 currently known species.
In the herbarium, Vanilla lindmaniana looked the same as Vanilla palmarum, so it’s no surprise that Vanilla lindmaniana was considered a synonym of Vanilla palmarum. But in the field, they behaved differently. In the Atlantic Forest and Caatinga, Vanilla palmarum consistently grew on Elaeis and Syagrus palms, while its relative in the Amazon, Cerrado, and Pantanal regions favored different hosts: Acrocomia, Attalea, and Mauritia palms. To document these and other differences systematically, he photographed and measured living specimens, combining traditional botanical techniques with detailed field observations.
It’s not simply their homes that differ. Up close, Vanilla lindmaniana reveals a specialised flower with a narrow channel to guide hummingbirds, while Vanilla palmarum has a flower better suited to bees. This also leads to other differences, Vanilla lindmaniana has larger flowers with round fruits, while Vanilla palmarum fruits are diamond-shaped. Being able to observe the plants in their habitat allowed Pansarin to capture details that couldn’t be found in a herbarium.
Does it matter that two similar orchids species are actually different from each other? It does if you want to preserve orchid diversity, because it means that one species cannot vbe replaced by another. In turn, that makes ongoing habitat loss in their respective homes a series problem, and now both species are now listed as Endangered. The research also suggests that herbaria may be holding other examples of closely related species under one label, which may be hiding other conservation needs. While herbaria are important, Pansarin’s work shows the importance of being able to observe plants in the wild to understand the diversity of ecosystems.
Pansarin, E.R. 2025. Vanilla lindmaniana and V. palmarum (Orchidaceae) are distinct allopatric species. Plant Ecology and Evolution 158(1): 53-62. https://doi.org/10.5091/plecevo.134103
Cross-posted to Bluesky & Mastodon.
Image: leocapin / iNaturalist. CC BY-NC 4.0
https://www.gbif.org/occurrence/4039382931
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