Matt 7:16 σταφυλην

Although the plural σταφυλας is present in a few mostly-related witnesses predating the 10th century (ℵ B C1 0281 f1 892 lat sy-h co) and followed by Bover, Greeven, Lachmann, Merk, Soden, and Tischendorf (8th), there are several reasons why the plural appears to be a secondary correction for the singular σταφυλην, which appears in all the other early witnesses (C*.2 E G K L M O S U V W X Δ Θ Π Σ Φ Ω 047 0211 Byz f13.35 565. 1424. 1500. 2224) and is followed by Vogels and Tischendorf (7th). First, the wording of the parallel in Luke 6:44b is so different that supposed harmonization in so many diverse witnesses to the singular form there is unlikely. Compare:

Matt 7:16b: μήτι συλλέγουσιν ἀπὸ ἀκανθῶν [σταφυλὰς/σταφυλὴν] ἢ ἀπὸ τριβόλων σῦκα;
Luke 6:44b: οὐ γὰρ ἐξ ἀκανθῶν συλλέγουσιν σῦκα, οὐδὲ ἐκ βάτου σταφυλὴν τρυγῶσιν.

Second, as Meyer (161) notes, the plural naturally could have originated in consequence of the plural συλλεγουσιν and especially in conformation to the plural συκα in the coordinate clause. Third, facilitating the alteration just mentioned are transcriptional considerations, which favor a possible original loss of the singular ending -ην in an early Egyptian archetype due to homoeoteleuton error from the particle η that follows (η...η). Finally, a few witnesses (L Ψ f13 it-c.e sy co go) make the same alteration (i.e., σταφυλας for σταφυλην) in Luke 6:44, an indication that the tendency of the alteration was not isolated, especially in the versions, where in an early diglot the chance of the plural form passing from a vernacular version into the Greek column greatly increases.