The coordinates can be passed in a plotting structure
  (a list with x and y components), a two-column matrix, a
  time series, ….  See xy.coords.  If supplied
  separately, they must be of the same length.
The coordinates can contain NA values. If a point contains
  NA in either its x or y value, it is omitted from
  the plot, and lines are not drawn to or from such points.  Thus
  missing values can be used to achieve breaks in lines.
For type = "h", col can be a vector and will be recycled
  as needed.
lwd can be a vector: its first element will apply to lines but
  the whole vector to symbols (recycled as necessary).