markeredgecolor

I often don't know which attributes can be used as

    > kwargs...

Any Artist method that starts with 'set_' can be set with a kwarg.
Eg, if set_markeredgecolor is a method, you can do
markeredgecolor=something as a kwarg.

Read through the classdocs at
http://matplotlib.sourceforge.net/classdocs.html for the object of
interest, eg for lines (Line2D), see
http://matplotlib.sourceforge.net/matplotlib.lines.html

Also, you can call set(object) on any object and it will return the
current properties and their values (see also example/set_and_get.py)

BTW, the set and get introspection functionality was recently moved out of
the pylab interface and now resides in matplotlib.artist so API
developers can use it as well

In [1]: lines = plot([1,2,3])

In [2]: set(lines)
    alpha: float
    antialiased or aa: [True | False]
    clip_box: a matplotlib.transform.Bbox instance
    clip_on: [True | False]
    color or c: any matplotlib color - see help(colors)
    dashes: sequence of on/off ink in points
    data: (array xdata, array ydata)
    data_clipping: [True | False]
    figure: a matplotlib.figure.Figure instance
    label: any string
    linestyle or ls: [ '-' | '--' | '-.' | ':' | 'steps' | 'None' ]
    linewidth or lw: float value in points
    lod: [True | False]
    marker: [ '+' | ',' | '.' | '1' | '2' | '3' | '4' | '<' | '>' | 'D' | 'H' | '^' | '_' | 'd' | 'h' | 'o' | 'p' | 's' | 'v' | 'x' | '|' ]
    markeredgecolor or mec: any matplotlib color - see help(colors)
    markeredgewidth or mew: float value in points
    markerfacecolor or mfc: any matplotlib color - see help(colors)
    markersize or ms: float
    transform: a matplotlib.transform transformation instance
    visible: [True | False]
    xclip: (xmin, xmax)
    xdata: array
    yclip: (ymin, ymax)
    ydata: array
    zorder: any number

In [3]: