Quercus

A living atlas of the oaks. One genus. Two hemispheres. A tangled tree.

The interactive atlas — the linked map, the phylogeny, the field guide — needs JavaScript to run. What follows is a static summary of what it holds.

Quercus draws every accepted species in the genus together with the georeferenced records that show where each one grows, two independent genus-wide phylogenies, IUCN Red List status, and the evidence for the hybridization and gene flow that make the oak tree of life so stubbornly hard to resolve.

What it holds

685 accepted species — the complete Quercus checklist from Kew's World Checklist of Vascular Plants, with 1,064 synonyms resolved to accepted names.
47,688 occurrence records — GBIF points across 624 species, split into 40,618 native and 7,070 introduced by each species' TDWG botanical range rather than by a bounding box.
Two genus-wide phylogenies — Hipp et al. 2020 (253 species, RAD-seq) and Liu et al. 2025 (314 species, Hyb-Seq), set side by side with a tanglegram and a support-weighted quartet concordance.
421 species assessed against the IUCN Red List, of which 109 are threatened — Critically Endangered, Endangered, or Vulnerable.
230 species placed to section — eight sections across two subgenera, following the Denk et al. 2017 classification.

Ways in

Tree — a radial cladogram of the genus; hover a clade, colour the tips by Red List status or leaf habit, then open any clade onto a linked map.
Map — the world atlas of occurrence records, coloured by status, section, leaf habit, or native range; click a point to identify the oak that made it.
Field Guide — a catalogue of all 685 species, filterable by section and Red List status, each with photographs and a detail card.
Worked example — the five European white oaks, read through five lenses, including the chloroplast lineages they share across species boundaries.
About — how the atlas is built, and the caveats worth knowing before you trust it.
Data — every source, with full citation, DOI, and licence.

Built on data from GBIF, Kew, the IUCN Red List, iNaturalist, WorldClim, and the published oak phylogenies; full citations on the Data page. Occurrence photographs are used under CC BY-NC with attribution. Code is MIT-licensed.