Philodendron spiritus-sancti is an aroid (family Araceae) endemic to the Atlantic Forest of the central mountainous region of Espírito Santo state, Brazil. The species is known for its unusual leaf shape and is highly coveted by horticulturists and private collectors for its ornamental value. It is rare in nature and is categorized as Endangered nationally and Critically Endangered in Espírito Santo but has not yet been evaluated for the IUCN Red List. Until 2023 only three natural populations were known, with a very restricted distribution that may be partly a result of overexploitation.

Following the recent global increase in the purchase of houseplants to create so-called urban jungles, the species began to gain more prominence in newspaper articles and social media. This attention resulted in a new observation recorded on iNaturalist (inaturalist.org), by author RdS, south of the known records of the species. In February 2024, we confirmed this record in Monumento Natural da Serra das Torres, a protected area of forest with mountainous and rugged terrain.

Philodendron spiritus-sancti in the wild. Photo: Vagner Faller.

The newly discovered population of P. spiritus-sancti is 128 km from the previously known records. We recorded at least 50 well developed individuals and many seedlings. The most impressive groups of individual plants are rupicolous, growing on a rocky wall. They dominate the wall and grow directly on the rocks, with associated rupicolous species such as Philodendron edmundoi, Griffinia concinna, Begonia spp. and bromeliads. The population has plants with both narrow and broad leaves growing together in a morphological gradient, resembling the species in the central mountainous region. Philodendron spiritus-sancti was previously considered a hemiepiphyte of the high forest canopy.

Our finding expands the known distribution of the species, demonstrates that it has more than one growth habit, and illustrates the potential of iNaturalist and citizen science as sources of data for improving knowledge of threatened species. This new record of P. spiritus-sancti also highlights the crucial role of protected areas for conservation.