title: Seaborn color palette with Pandas groupby and .plot function
body: <p>I am having a very frustrating problem when trying to plot some data with a seaborn color palette.  My workflow is to perform a groupby operation on my dataframe, and plot each group as its own curve using code like this:</p>
  
  <pre><code>import seaborn as sns; sns.set_style('whitegrid')
  f, (ax1, ax2) = plt.subplots(1, 2, sharey=True, figsize=(16, 6))
  
  inner = d.groupby(['dr_min', 'dr_max'])
  n = len(inner)
  cmap = sns.color_palette("Blues", n_colors=n)
  inner.plot(x='limit_l', y='lccdf', ax=ax1, color=cmap, legend=False)
  inner.plot(x='limit_r', y='rcdf', ax=ax2, color=cmap, legend=False)
  </code></pre>
  
  <p>I expect to see a curve for each one of my groupby parameters with clear shades from the color map, as seen here:
  <a href="https://i.stack.imgur.com/Pg5KW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Pg5KW.png" alt="enter image description here"></a></p>
  
  <p>Instead, my curves look below, with no color grade at all.  Can anyone help me understanding why this is happening?</p>
  
  <p><a href="https://i.stack.imgur.com/nTtU5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nTtU5.png" alt="enter image description here"></a></p>