poke greens 是什么意思？

下面的小段取自2013湖南高考题，不太清 poke greens 是什么意思，查了词典，其中 poke 在词典中没有对应的意思，请教专家老师指点，谢谢！

From the moment of my arrival at the little school, all gloom (忧郁) disappeared. Upon arriving at Dorothy’s classroom, I was greeted with smiling faces and treated like a queen. The children had been prepared to show me their latest projects. Dorothy told me with a big smile that they were serving poke greens salad and cornbread for “dinner” (lunch). In case you don’t know, poke greens are a weed-type plant that grows wild, especially on poor ground. 

问题：Upon arriving at the classroom, the author was cheered up by ______.

A. a warm welcome

B. the sight of poke greens

C. Dorothy’s latest projects

D. a big dinner made for her (2013湖南卷阅B)