Well! I sure didn't cover myself with glory carefully reading the question!
suppressPackageStartupMessages(library(dplyr))
suppressPackageStartupMessages(library(ggplot2))
suppressPackageStartupMessages(library(ggthemes))
box <- ggplot(data=iris, aes(x=Species, y=Sepal.Length))
box + geom_boxplot(aes(fill=Species)) +
ylab("Sepal Length") + ggtitle("Iris Boxplot") +
stat_summary(fun.y=mean, geom="point", shape=5, size=4) +
theme(axis.text.x = element_text(angle = 90, face = "italic"))
Created on 2020-02-11 by the reprex package (v0.3.0)
(corrected by removing theme_tufte() (to get a white background)