achilquilitl.

Headword: 
achilquilitl.
Principal English Translation: 

an herb that grows in potable water (see Molina)

Alonso de Molina: 

Achilquilitl. yerua que se cria en agua comestible.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 2r. col. 1. Thanks to Joe Campbell for providing the transcription.