Legend has it that there was a woman in ancient times, because her husband died by the side and cried under the tree and turned into red beans, so people called her "Xiangsisi".
"Southland" (South) is not only the origin of red beans, but also the place where friends are.
It is often used to describe lovesickness in Tang poetry. And "lovesickness" is not limited to the scope of love between men and women, but also exists among friends. The first sentence begins with "when those red berries come in spring", which insinuates the following acacia.