I am trying to use "tabu" (specifically, longtabu) to create tables. I am attempting to follow Government Printing Office Style Manual guidance, 13.21: "Boxheads [i.e., table column headers] are centered horizontally and vertically." Here is an example from the manual itself:
Here is a pared-down example of the table I am working on. I haven't been able to figure out how to center the headers either vertically nor even horizontally:
\documentclass{article}
\usepackage{ctable}
\usepackage{longtable}
\usepackage{tabu}
\begin{document}
\begin{longtabu} to \textwidth{ X[24] X[106] X[16] X[46] }
\toprule
\rowfont[c]\normalsize Symbol & Common Name \strut\newline\strut Scientific Name & ODA List/Target & Mapping Protocol \\
\midrule\endhead
\scshape{aecy} & jointed goatgrass \strut\newline\strut\quad \emph{Aegilops cylindrica} & B & Mandatory \\
\scshape{aetr} & barbed goatgrass \strut\newline\strut\quad \emph{Aegilops triuncialis \emph{var.} triuncialis} & A/T & Mandatory \\
\scshape{brte} & cheatgrass \strut\newline\strut\quad \emph{Bromus tectorum} & & Discretionary \\
\bottomrule
\end{longtabu}
\end{document}
I get as follows:
The headings are neither vertically nor horizontally centered. I attempted to use \rowfont[c], but this seems ineffective. I do not know how to vertically center. Other questions along the same line are not clear to me. Can anyone help? Thanks!