"Memory Doctor" joke

As my elderly aunt and uncle strolled downtown one afternoon they run into their old friends. They spend some time discussing this and that when one friend asks my uncle where they has been. "We just left the office of our memory doctor"

"Memory doctor? What is that all about?"

"Well" replies my uncle "As you know we are getting up there in age, and our memory just isn't as sharp as it once was."

"Is the doctor effective?"

"Oh, yes, he's wonderful."

"Really. You know, my memory is not too sharp these days either. Maybe I'll pay him a visit. Whats his name?"

"Oh. Uh. Well." replies my uncle. "Um. You know those things that grow out of the ground?".

"You mean trees?"

"Kind of, but smaller."

"You mean a bush?"

"Yes, a bush or a plant, but. .. Um. .. You know, more colorful."

"A flower?".

"Yes. A flower. But it has sharp, pointy, sticky things growing on it."

"Thorns?"

"Yes. Thorns."

"Oh!" says the friend "A rose!"

"Yes, exactly" says my uncle, turning to his wife "Hey Rose, what is the name of our memory doctor?."