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Artemisia, along with Chenopodiaceae is the dominant component growing in the desert and grassland of the Northern Hemisphere. The Chenopodiaceae/Artemisia (C/A) pollen ratio is a traditional bio-indicator to evaluate environmental aridity prior to meteorological records. However, when applying the C/A ratio from the original point in the Middle East to other regions, the validity was questioned. Compared with Chenopodiaceae pollen, which is inversely proportional to precipitation, Artemisia pollen with its diverse habitats is probably responsible for this uncertainty.

Here we provide the Artemisia pollen morphological datasets covering 36 species from 9 clades and 3 outgroups under a phylogenetic framework to ensure maximum variation coverage and their source plant habitat ranges. The new pollen classification with a key to the pollen types of Artemisia was established by hierarchical cluster analysis. The Artemisia pollen classification (1) improves the resolution of bio-indicators in deep-time environmental assessment; (2) reveals that the diverse habitats colonized by Artemisia could be responsible for the uncertainty of the C/A pollen ratio in different regions; (3) changes the traditional concept of Artemisia being restricted to arid and semi-arid environments.

We hope to establish an open dataset that welcomes new Artemisia data from all over the world in the future for better serving the global paleoenvironment assessment and refined reconstruction of paleovegetation.