diff --git a/gnu/packages/statistics.scm b/gnu/packages/statistics.scm
index cdf080fe4f..1b9ce60efe 100644
--- a/gnu/packages/statistics.scm
+++ b/gnu/packages/statistics.scm
@@ -3607,6 +3607,8 @@ memory usage.")
      `(("r-ggplot2" ,r-ggplot2)
        ("r-gridextra" ,r-gridextra)
        ("r-viridislite" ,r-viridislite)))
+    (native-inputs
+     `(("r-knitr" ,r-knitr))) ; for vignettes
     (home-page "https://github.com/sjmgarnier/viridis")
     (synopsis "Matplotlib default color map")
     (description