The headword phrase is unattested elsewhere. LSJ s.v. puri/ths (2) cites Aetius 2.263 for the plural form, but this is not correct according to Olivieri's edition of the text of Aetius. Aetius does refer to oi( e)k purw=n a)/rtoi ('breads made out of wheats') at 2.240 and a)/rtoi pituri=tai ('bran breads') at 2.265. A closer parallel is found in the anonymous medical treatise De alimentis 12: oi( puri=tai tw=n a)/rtwn ('those of the breads that are wheaten').
[2] A secondary lemma, probably associated with the headword phrase because of the superficial similarity between the words for pyrite (puri/ths or puri=tis li/qos) and wheaten (puri/ths). In reality the words are of different origins, the former having a short upsilon in the first syllable, the latter a long upsilon. In late Greek pronunciation the phonological distinction between the words would not have been recognized. See also pi 3217, where the word for pyrite has a slightly different spelling, and Hesychius pi4430, where in Latte's edition the word for 'stone' appears as a gloss for the word for 'pyrite'.
[3] This addition is lacking, Adler reports, in mss AFV. It is probably copied from the entry to which it refers, alpha 4554. The phrase 'invisible [i.e. soft, dull] light' is from Sophocles, Philoctetes 297.