In recording Jesus’ warnings about “false prophets” (probably fake disciples), Matthew contrasts akantha (thorn bushes) with staphyle (grapes), and tribolos (thistle) with sykon (figs) (Matt 7:16); whereas, Luke contrasts akantha (thorn bushes) with sykon (figs), and batos (bramble bush) with staphyle (grapes) (Matt 6:44).
You will know them by their fruits. Do men gather grapes from thorn bushes or figs from thistles? (Matt 7:16, NKJ).
For every tree is known by its own fruit. For men do not gather figs from thorn bushes, nor do they gather grapes from a bramble bush (Luke 6:44, NKJ).
Either the translators were unable to agree on spiny plant identification or Jesus may have referred to different plants on different occasions when using the same teaching illustration. He used a similar saying when confronted by accusers in Matthew 12:24-37; see verse 33.