Question

Hello, honored Rabbi,
A question on the Mishnah in tractate Kilayim, chapter 2, mishnah 11: “Grain leaning over grain, vegetables over vegetables, grain over vegetables, vegetables over grain—all are permitted except for Greek gourd. Rabbi Meir says: also cucumbers and Egyptian beans. And I find their words more convincing than my own.”
 
My question is: what exactly did Rabbi Meir do here? Did he cite the words of his teachers who taught him this and claim that he disagreed with them, but in the end leaned toward the view of the first tanna?
Was he quoting something he himself had said in the past and then retracting it (because this was the first time he had been exposed to the view of the first tanna mentioned above)?
 
Thank you