To cite package ‘taxonlookup’ in publications use:

  Cornwell W, FitzJohn R, Pennell M (2019). _taxonlookup: A
  dynamically-updating versioned taxonomic resource for vascular
  plants_. R package version 1.1.5,
  <https://github.com/traitecoevo/taxonlookup>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {taxonlookup: A dynamically-updating versioned taxonomic resource for vascular
plants},
    author = {Will Cornwell and Rich FitzJohn and Matt Pennell},
    year = {2019},
    note = {R package version 1.1.5},
    url = {https://github.com/traitecoevo/taxonlookup},
  }