The Collaborative International Dictionary of English v.0.48:

Phycoerythrin \Phy`co*e*ryth"rin\, Phycoerythrine
\Phy`co*e*ryth"rine\, n. [Gr. fy^kos seaweed + E. erythrin,
   -ine.]
   A red coloring matter found in algae of the subclass
   Florideae.
   [1913 Webster]