plotYearMatrix: Returns the image object to show the heat map of years...
In dicook/phyViz: Phylogenetic Visualization

Returns the image object to show the heat map of years between the inputted set of vertices

1 2	plotYearMatrix(varieties, tree, xLab = "Variety", yLab = "Variety", legendLab = "Difference in years")

`varieties`	subset of varieties used to generate the heat map
`tree`	the data tree (in data frame format)
`xLab`	string label on the x axis (default is "Variety")
`yLab`	string label on the y axis (default is "Variety")
`legendLab`	string label on the legend (default is "Degree")

data(sbTree)
varieties=c("Bedford", "Calland", "Narow", "Pella", "Tokyo", "Young", "Zane")
p = plotYearMatrix(varieties,sbTree,"Variety", "Variety", "Degree")
p + ggplot2::scale_fill_continuous(low="white", high="darkgreen")