Below are some links to books about pleurothallids that you might want to add to your library.
Masdevallia and Affiliates
by Lisa Thoerle
Icones Pleurothallidinarum Volume 30
by Carlyle A. Luer
Masdevallia and Affiliates explains the newly accepted divisions of Masdevallia that Carl Luer outlined in Icones vol 28.
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