ixpoxcauhcayotl.

Headword: 
ixpoxcauhcayotl.
Principal English Translation: 

bread mold or something similar (see Molina)

Orthographic Variants: 
ixpuxcauhcayotl, ixpoxcauh cayotl
Alonso de Molina: 

ixpoxcauhcayotl. moho de pan, o de cosa assi.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 47r. col. 1. Thanks to Joe Campbell for providing the transcription.

puxcaui [poxcahui] = enmohecerse

Attestations from sources in Spanish: 

ixpoxcauh cayotl = un hongo o moho
Gastón Guzmán, Los nombres de los hongos (1997), 220.